First mod, by kind

Fifteen content kinds ship with the SDK, and every one of them starts the same way: a folder under mods/, a manifest.toml, rsmm apply. What changes per kind is the handful of fields in the [[content]] block — and the way you prove the change actually landed.

This page is one starting mod per kind. Each snippet is a complete manifest.toml: copy it into mods/<id>/manifest.toml, adjust the ids, apply.

The loop, every time

./rsmm new MyMod          # scaffold mods/MyMod/
./rsmm lint MyMod         # manifest, asset paths, confidence gate
./rsmm restore --all      # back to vanilla first — restore wipes the loader
./rsmm apply              # install this mod's files
./rsmm install-loader     # re-plant the loader (apply does not)
./rsmm run                # launch through Steam

restore --all before every apply is not superstition: it is how you avoid testing a mod on top of the last one’s leftovers, and it is the uninstall path you should expect to work at the end.

`item` — a new magical object

What the player sees. A brand-new item in the compendium that drops, is offered by chests, and works.

Or build it on a page. The Items tab of rsmm editor, or the web editor, writes this block from a picked base item.

[mod]
id          = "SwiftAttacks"
name        = "Swift Attacks"
version     = "0.1.0"
author      = "you"
description = "A faster cousin of the Ace card."

[[content]]
kind  = "item"
id    = "Swift_Attacks"      # SAME BYTE LENGTH as base (13) — see the trap
base  = "Damage_Attack"
name  = "Swift Attacks"
description = "Attack speed, and nothing else."
value_patches = [["Attack Speed Value", 0.15, 0.30]]

Prove it. Start a run, open the compendium — the item is listed. Then take it from a chest and watch the value you patched.

Trap. The clone pipeline is length-preserving: id must match base in byte length. Browse bases with ./rsmm items list, and a base’s editable value labels with ./rsmm items show <base> — a label marked shadowed accepts the edit and changes nothing in game.

Change the shipped item instead. mode = "replace" takes the same fields but edits the base itself rather than adding a copy beside it: no new id, the base keeps its rarity, and name/description rewrite the text the item already shows. The shipped file is backed up and comes back when the mod is turned off. The editor’s Replace this item / Make a copy switch picks between the two.

[[content]]
kind          = "item"
id            = "Damage_Attack"
mode          = "replace"
base          = "Damage_Attack"
value_patches = [["Attack Speed Value", 0.15, 0.30]]

Also does the opposite. mode = "ban" with items = [...] removes vanilla items from the catalog instead — the multiplayer-correct way to disable one.

`talent` — retune a talent

What the player sees. The same talent card, different numbers.

Or build it on a page. The Talents tab of rsmm editor, or the web editor, lists every value a hero has and writes this block (and skill blocks for renamed cards).

[mod]
id          = "JulietBuff"
name        = "Juliet Talent Buff"
version     = "0.1.0"
author      = "you"
description = "Juliet's dash shield lasts longer."

[[content]]
kind = "talent"
id   = "dash_shield_duration"
hero = "Juliet"
file = "Hero_Juliet.entity"
value_patches = [
  { label = "Skill Dash Shield Duration", old = 6.0, new = 9.0 },
]

Prove it. Take the talent in a run and read the card: the number moves.

Trap. A label can exist in several of a hero’s entity files, and some values are shadowed by an override node — the writer handles both, but you have to name the label exactly, and old must match the shipped number or the apply stops. Find labels, their files and their numbers with ./rsmm talents Juliet --grep shield, and see the talent tutorial for the card-text placeholders.

`ability` — change a shipped hero’s abilities in place

What the player sees. The same hero, an ability that behaves differently: a number changed (a hit’s stagger, a cooldown, a damage multiplier) or a link rewired. No second hero is added, so the change applies to every run with that hero, and rsmm restore puts the originals back.

Or build it on a page. The Abilities tab of rsmm editor, or the web editor: set a number, pick “Change the original hero”, and Save to mod writes this block. Choose “Make a separate custom hero” there when you want a copy (kind = "hero") instead, or an ability copied with clone.

[mod]
id           = "BeowulfFireballNerf"
name         = "Beowulf Fireball Nerf"
version      = "0.1.0"
author       = "you"
description  = "Beowulf's Fireball staggers less."
experimental = true

[[content]]
kind = "ability"
id   = "BeowulfAbilities"
hero = "Beowulf"

[[content.abilities]]
set    = "Stagger Power Selector.entries[0][1]"
value  = 25
entity = "Hero_Beowulf_Ultimate_2_Fireball"

Prove it. Use the ability in a run and look at the effect: here the fireball hits stagger enemies less than the 50 it ships with.

Trap. A hit’s numbers often live in another file of the hero (the fireball’s stagger is in its own projectile file, hence entity), and a selector’s number is addressed as Part.entries[i][j], not Part.value. The editor’s search lists matches in every file of a hero. clone steps are refused here: copying an ability adds parts that only a custom hero builds. The kind is experimental until the steps are proven in game.

`entity` — edit any shipped entity in place

What the player sees. One shipped object behaving differently: a boss spawner, a camp, a UI. It takes the same set / link / add_link / remove_link steps as ability, aimed at one entity file that is not a hero’s. rsmm restore puts the original back.

[mod]
id           = "NoOvertimeTint"
name         = "No Overtime Tint"
version      = "0.1.0"
author       = "you"
description  = "Removes the red screen tint before and during overtime."

[[content]]
kind   = "entity"
id     = "boss_spawner_no_tint"
entity = "Objects/Map_Boss_Spawner/Map_Boss_Spawner_Graph_Model"

[[content.steps]]
remove_link = "State FX PreOvertime.while_active[1]"

Prove it. Let a chapter run into overtime: the screen stays its normal colour while the banner, minimap ping and music still arrive.

Trap. entity is the path under EntitySettings (.entity.ot optional). Part names and link indices are the ones rsmm entity-graph prints for that file, and removing a link shifts the later indices of the SAME list, so remove from the end first or list one step per field. clone steps are refused.

`mesh` — put your model in the game

What the player sees. A shipped prop, weapon or body wearing your geometry.

[mod]
id          = "ShrineBlock"
name        = "Runestone Block"
version     = "0.1.0"
author      = "you"
description = "Replaces a ruin block with a runestone."

[[content]]
kind   = "mesh"
id     = "shrine_over_ruin_block"
target = "Scenery\\DarkHills\\Wall_Ruins_Block_Small_A.fbx"
model  = "art/shrine.glb"

Prove it. Walk a chapter that places the target mesh. Your shape is there, lit and textured, with no other change.

Trap. The override is global: every tile that places that mesh now shows yours. And replacing a character needs the right transform.skin — "gltf" when you rigged to the game’s bone names, "rigid" when you did not. The default ("transfer") assumes your mesh occupies the same space as the one it replaces, and shreds a differently-shaped body on the first animation frame.

`animation` — replace a clip with your own motion

What the player sees. A shipped animation, such as Piper’s dash, playing your motion.

[mod]
id           = "PiperSpin"
name         = "Piper Spin Dash"
version      = "0.1.0"
author       = "you"
description  = "Piper spins through her dash."

[[content]]
kind   = "animation"
id     = "piper_dash"
target = "Characters\\Heroes\\Piper\\Animations\\Piper_Dash_Default.fbx"
source = "anims/piper_dash.glb"

Prove it. Dash in a run: the move plays your keys.

Authoring in Blender or Maya. rsmm export-character Piper writes one .glb with the real armature (the game’s bone names, hierarchy and bind pose), the skinned body with its full materials (colour, normal and metal/roughness/AO maps), the weapon or prop on the bone that carries it, and every clip that fits that rig. --skin Combat exports a skin’s look instead: its materials, its body and its weapon (--list-skins names them). A piece on a skeleton of its own, like the Combat cloak, comes in as a second armature at its own origin: the entity does not say where it hangs, so place it by hand. It imports as a posable, animated character.

For anything that is not a hero, use rsmm export-model. It exports any of the game’s 3,001 models: scenery, props, enemies, NPCs and mechanisms like chests. Each comes with its full materials, and a rigged one also gets its skeleton and every clip in its folder that fits it. rsmm export-model --list Ogres shows what there is, and rsmm export-model OgreHuman_GEO writes one model. rsmm export-model --all -o export/ writes every model into a tree laid out like the game’s folders. That run is long, and --no-textures makes it much faster.

Two settings matter:

Set the scene frame rate to 60 before importing. Clips mix a 30 fps grid with 60 fps keys where something snaps (Piper’s weapon flips in half a frame). At 24 or 30 fps Blender drops those keys. At 60, all 45 of Piper’s clips came back within 0.3 degrees after an import and export.
Export glTF with animations, keeping the action names.

Then rsmm import-character edited.glb --mod my-piper (add --skin Combat if you exported a skin) writes the mod for you. It cooks every action, compares its sampled poses with the shipped clip of the same name, and keeps only the ones that moved more than --threshold degrees (default 1; an untouched round trip stays under 0.5). The body is kept when its vertices no longer match the shipped body. Each kept clip becomes a block like the one above, the body a kind = "mesh" block with transform = { skin = "gltf", submeshes = "map" } (weights bind by bone name, each submesh keeps its own material), and the .glb is copied into the mod. It never overwrites an existing mod without --force.

Trap. Bones are matched by name, and the target clip is the template: it decides which bones exist. A bone your file does not animate is held at the target’s first pose (strict = true makes that an error). A bone the target lacks is refused. Like mesh, the override is global: everything that plays that clip plays yours.

`poi` — a structure in a chapter

What the player sees. A shrine / cauldron / camp appearing on a map that never had one.

A POI is a folder, and needs no [[content]] block at all. The mod’s manifest.toml is just the [mod] table; everything else lives beside the model:

mods/MyShrine/
  manifest.toml
  pois/runestone_shrine/
      poi.toml
      model.glb
      albedo.png  normal.png  mra.png  icon.png

This is the shrine that was proven in game end to end: tile, mesh, minimap marker and interaction.

base     = "Dark_Hills/6x6_Crystal_01"   # the tile it is generated as
chapters = ["Dark_Hills"]
kinds    = ["Crystal"]                   # which generator slots it may fill
copies   = 1

replaces      = "Objects_Common\\DreamCrystal_Medium.entity.ot"
entity_base   = "DarkHills\\SceneryObjects_DarkHills\\Wall_Ruins_Block_Small_A.entity.ot"
material_base = "Scenery\\DarkHills\\M_Walls_Ruins.mat.ot"
transform     = { fit = "rig", scale = 2.0 }
interactive   = true

[slots]
albedo = "Scenery\\DarkHills\\T_Walls_Ruins_ALB.tga"
mra    = "Scenery\\DarkHills\\T_Walls_Ruins_MRA.tga"
normal = "Scenery\\DarkHills\\T_Walls_Ruins_NRM.tga"

[marker]
icon          = "icon.png"
reveal_radius = 20000.0

Prove it. Run the chapter and look at the minimap: the icon draws, the prop is interactable, and a mod can confirm its own placements from Lua (R.poi.placed).

Trap. kinds must be slots that tiles of the base’s size actually fill — a 40×40 base can never fill a 6×6 Fountain slot, and the emit says so. weight is a tier, not a spawn rate — raising it to make a POI commoner is backwards. Use copies, which buys pool entries one for one. Browse bases with ./rsmm poi list.

`enemy` — change what a camp spawns

What the player sees. Every Dark Hills camp full of treants, or a brand-new creature among the usual ones.

[mod]
id           = "Treantfall"
name         = "Treantfall"
version      = "0.1.0"
author       = "you"
description  = "Dark Hills is a forest, and it has opinions."

[[content]]
kind   = "enemy"
id     = "treant_everywhere"
mode   = "override"          # rewrite a retail population in place
pools  = ["Dark_Hills"]
entity = "Enemies\\Treant\\Standard_Root_Treant.entity.ot"

Prove it. Load the chapter and fight the first camp: every creature in it is a treant. List a biome’s creatures with ./rsmm enemies pool Dark_Hills.

Trap. power (old name weight) is a creature’s cost against the camp’s power budget, not its spawn odds. A mode = "clone" enemy set to 20 was priced out of every gnoll camp and never appeared. Leave it unset to keep the base’s cost. Imported creatures can also bring projectiles and attack zones the destination chapter never loads; see Custom enemies.

`reward` — ban or retune what spawns at reward points

What the player sees. No more locked chests in Avalon, or fewer of them.

[mod]
id           = "NoLockedChests"
name         = "No Locked Chests"
version      = "0.1.0"
author       = "you"
description  = "Chests spawn unlocked."

[[content]]
kind = "reward"
id   = "avalon_rewards"
base = "Camp_Rewards_Avalon_Update5"
ban  = ["Chest_Locked"]

Prove it. Play the chapter and count what the reward points produce. Pick a number the game cannot reach on its own — counts = { 2 = [3, 3] } gave three astrolabs where Dark Hills normally has at most one.

Trap. This bans reward objects, never talent or item cards — that lever is the item catalog (kind = "item", mode = "ban"). Each ban entry must match something, deliberately: a typo fails the emit instead of silently doing nothing. Use the _Update5 def: the plain Camp_Rewards_<Biome> ones are never loaded, and the SDK refuses them.

`shop` — change the Sandman’s stock and prices

What the player sees. Different items in the in-run vendor, at your prices.

[mod]
id           = "CheapSandman"
name         = "Cheap Sandman"
version      = "0.1.0"
author       = "you"
description  = "Everything is half off."

[[content]]
kind        = "shop"
id          = "sandman"
price_scale = 0.5            # every Sandman item, half price

Prove it. Find the Sandman in a run and open the shop.

Trap. There is one Sandman, so a mod declares at most one shop. The seven generators (minor, medium, major, the *_duplicate and *_object variants) each decide count, quality and flag pool separately — changing one does not move the others. A slot’s count can go down but never above what it ships with: the shop screen has a fixed number of widgets per slot.

`tilegen` — a chapter’s map-generation recipe

What the player sees. More camps, more wells, a differently-shaped map.

[mod]
id           = "BusyHills"
name         = "Busy Dark Hills"
version      = "0.1.0"
author       = "you"
description  = "Fewer, hand-placed-feeling camps."

[[content]]
kind    = "tilegen"
id      = "camps"
chapter = "DarkHills"
[content.kinds.Camp]
count = 2                 # camps placed by the kind pass
[content.fill]
"40x40" = []              # leftover big slots stay empty instead of
"64x64" = []              # becoming camps

Where tiles come from. Generation runs in two passes, and tiles can pull in more tiles:

Kind pass. Each kind places up to its count.
Fill pass. Every footprint group then fills each slot still empty with a tile carrying the group’s flags. Dark Hills fills 40x40/64x64 with Camp, which is why an unedited map shows 8-9 camps against a Camp count of 5. fill = { "<WxH>" = [] } turns it off for that group.
Tile constraints. A placed tile can require others nearby. Start places one Story tile, and the Wood House story tile then places 3 Treant camps. The recipe doesn’t control these.

Flag quotas are caps (at most N), so raising one never adds tiles.

Prove it. Start a run in that chapter and count what generated. R.poi.on_generated + R.poi.placed hand you every placed tile by name, so the count can come from the spawner itself instead of the minimap. Count camps by source: Treant camps next to the Wood House come from its constraint, not the recipe.

Trap. Edits are keyed by name and re-applied to the shipped recipe every time, so a name the recipe no longer has fails the emit rather than landing on whatever now sits at that index. The Map tab of ./rsmm editor writes these blocks for you from a 3D view of the chapter.

`game_mode` — reorder the chapters of a run

What the player sees. A run that starts in Avalon.

[mod]
id           = "AvalonFirst"
name         = "Avalon First"
version      = "0.1.0"
author       = "you"
description  = "Chapter order: 2, 0, 1, 3."

[[content]]
kind     = "game_mode"
id       = "AvalonFirst"
base     = "All_Chapters"
chapters = [2, 0, 1, 3]

Prove it. Start a new run and read the chapter you land in.

Trap. This rewrites the game’s one run order in place — there is no second mode to pick from a menu, so the id is only a label, and two mods that both set chapters (or a map mod with chapter = N) collide on the same file. A FIXED order is data-safe; per-run randomisation is not (it needs engine RNG and multiplayer determinism). Proven in game: skipping chapters and running them out of order. Each chapter may appear once; a repeat is refused, because the game skips it.

`map` — make a chapter play a cloned map

What the player sees. A chapter that plays a mapdef of your own. Today it looks like the base map: the clone reuses the base’s terrain and still draws its tiles from the base’s pool.

[mod]
id           = "TwilightHills"
name         = "Twilight Hills"
version      = "0.1.0"
author       = "you"
description  = "Chapter 1 plays a Dark Hills clone."
experimental = true

[[content]]
kind    = "map"
id      = "Twilight_Hills"
base    = "Dark_Hills"   # Dark_Hills, Storm_Island, Avalon or Baba_Yaga
chapter = 0              # 0 Dark Hills, 1 Storm Island, 2 Avalon, 3 Baba Yaga

Prove it. R.maps.chapters() lists each chapter’s map: the one you repointed says resref and resolves to a mapdef that is not the vanilla one.

Trap. chapter overrides All_Chapters as a whole file, so it conflicts with a game_mode edit in another mod (last writer wins). Tile generation follows the base’s tile-generation level back to the ORIGINAL mapdef, so pool edits on the clone do nothing yet, and tribe has shown no visible effect. To change what an existing chapter generates, tilegen and poi are the proven tools.

`skill` — relabel a talent

What the player sees. A talent with your name and description on the level-up card and in the Skill Menu.

[mod]
id           = "DiveRename"
name         = "Dive, Renamed"
version      = "0.1.0"
author       = "you"
description  = "Attack Dive becomes Meteor."

[[content]]
kind        = "skill"
id          = "meteor"
hero        = "Aladdin"
source      = "Attack Dive"
name        = "Meteor"
description = "Come down harder."

Prove it. Open the hero’s Skill Menu — the new text is there.

Trap. Relabel renames an EXISTING talent — a hero’s talent count is fixed. mode = "clone" (add a row) and mode = "repoint" (rename the herodef row) are refused: the first crashed the game, and the second changes nothing visible, because the name shown comes from the hero entity’s controller key.

`modifier` — a custom run mutator

What the player sees. A new toggle on the challenge screen — in theory.

[mod]
id           = "DoubleXp"
name         = "Double XP"
version      = "0.1.0"
author       = "you"
description  = "A relabelled MoreExperience."
experimental = true

[[content]]
kind        = "modifier"
id          = "DoubleXp"
base        = "MoreExperience"
name        = "Double XP"
description = "Twice the experience, twice the regret."

Prove it. Open the challenge screen and look for the row.

Trap. The def cooks and loads; a NET-NEW modifier appearing in the UI is the unproven part — the slot count looks pre-sized to the vanilla set. A modifier’s effect is hardcoded C++ keyed by an entity-value id, so a clone reuses an existing behaviour; new behaviour is layered in Lua via R.modifier.

`melody` — retune one of the Piper’s melodies

What the player sees. A lost melody that grants a different effect.

[mod]
id           = "HealierHeal"
name         = "Healier Heal"
version      = "0.1.0"
author       = "you"
description  = "Fully Heal reveals the map instead."
experimental = true

[[content]]
kind   = "melody"
id     = "fully_heal"
base   = "Fully_Heal"
effect = "Reveal_Map"        # must be another retail melody's stem

Prove it. Play the Piper, collect that melody, use it.

Trap. There are exactly twelve melodies and twelve icons, indexed by a dense enum — so there is no thirteenth. This kind edits the twelve that exist and refuses to pretend otherwise.

`boss` — make a boss arena fight another boss

What the player sees. The Dark Hills ghoul den, with the Storm Island giant crab waiting at the bottom.

[mod]
id           = "CrabDen"
name         = "Crab Den"
version      = "0.1.0"
author       = "you"
description  = "The ghoul den fights the giant crab."

[[content]]
kind    = "boss"
id      = "crab_den"
base    = "Boss_Marsh_Ghoul"
becomes = "Boss_Crab"

Prove it. Enter the arena base belongs to and see who is waiting. (Proven with base = "Boss_White_Lady": her shrine raised its arena around the crab and paid its reward when the crab died.) base must be one of the bosses whose arena picks them by flag alone: Boss_Crab, Boss_Marsh_Ghoul, Boss_Wolf, Boss_White_Lady. becomes can be any boss definition.

Trap. Quest bosses, the Jinn and the three-part witch fight are refused as base: something besides the definition names their entity, so swapping it would split the fight from whatever holds that reference. The swap is global — every run fights the new boss there.

`hero` — add a hero to the roster

What the player sees. A new portrait on the hero-select screen. With only a base it is an exact copy of that hero; the fields under “A hero of its own” give it its own name, body, textures, portrait and gameplay entity.

[mod]
id           = "MoreHeroes"
name         = "More Heroes"
version      = "0.1.0"
author       = "you"
description  = "A second Piper."

[[content]]
kind = "hero"
id   = "Zz_Piper_Clone"
base = "Piper"

Prove it. Open the hero-select screen: one more portrait than before. From Lua, #R.defs.instances("oCDtHeroDefinition") goes from 12 to 13.

Trap. The roster is every hero the game has loaded, and heroes load only through the LiveOps versiondef’s hero list, which apply appends to. Dropping a herodef file in without that loads nothing. The new hero takes the next index, which no save has unlocked, so test with the unlock-heroes mod. Paid DLC hero (Merlin) is a base only when the block says dlc_owner = true: the clone plays for anyone who installs the mod, so share it only with players who own the DLC.

A hero of its own

Everything past base turns the copy into a hero of its own. The fields below are not yet proven in game. Only the plain copy above is.

[[content]]
kind        = "hero"
id          = "Nyx"                       # letters and digits: it names Hero_Nyx
base        = "Piper"                     # whose moves she has
name        = "Nyx"
description = "Piper's moves, her own look."
model       = "art/nyx.glb"               # body, rigged to Piper's skeleton
albedo      = "art/nyx_albedo.png"        # also: mra, normal
portrait    = "art/nyx_portrait.png"      # select screen + in-run

# A weapon of her own. The key is the base's graphic object; `rsmm
# export-character Piper` lists it as an attachment.
[content.weapons."Weapon In Left Hand Mesh"]
model  = "art/nyx_flute.glb"
albedo = "art/nyx_flute.png"

# Her own moves: a clip of Nyx's alone, the base keeps its own.
[content.animations.Piper_Dash_Default]
source = "art/nyx_moves.glb"
clip   = "Piper_Dash_Default"             # the action's name in the .glb

# Outfits fill the skin slots after Default, in order.
[[content.outfits]]
name   = "Frost"
albedo = "art/nyx_frost.png"

[[content.outfits]]
name   = "Mercenary"
model  = "art/nyx_mercenary.glb"      # a body of its own
albedo = "art/nyx_mercenary.png"

# Her numbers. `rsmm export-character Piper --list-values` lists them.
[content.values]
"Ultimate Power 2 Cooldown Max" = 30
"Trait Ability Pets Per Spawn Default Amount" = 3
"Hero_Piper_Projectile/Lifetime Duration" = 0.8   # one entity only

# What her abilities use: a VFX, a sound, a mesh, anything her entities name.
[content.references]
"Settings\\Heroes\\Hero_Piper_FX\\Piper_Note_Day_01.vfx.ot" = "Settings\\Heroes\\Hero_Juliet_FX\\Juliet_Basic_Bullet_Trail_01.vfx.ot"

# How her abilities are wired: copy, set and rewire parts, by the names
# `rsmm entity-graph Piper` shows. Applied in order.
[[content.abilities]]
clone = "Ability Secondary"          # a group, or a list of parts
as    = "Echo"                       # new group; each part gets " Echo"

[[content.abilities]]
set   = "Primary Ability Shots Delay.value"
value = 0.2                          # on a linked number, replaces the link

[[content.abilities]]
entity = "Ice_Clone"                 # another file of the family
set    = "Explosion Attack Traverser.obj_2[3]"
value  = 4.0                         # the n-th number inside a part's settings

[[content.abilities]]
link  = "Primary Ability Shoot Timer.on_end"
to    = "State Secondary Ability Echo"

name / description are added to the base’s text bank as Hero_<id>_Name / Hero_<id>_Desc in every language (English text for all of them), and the new herodef points at them.
model is the body. Start from rsmm export-character Piper, edit the mesh in Blender on Piper’s skeleton, and export. Bones are matched by name, and a weapon left in the file is ignored (it is a separate object in game). Every skin slot shows this body.
albedo / mra / normal replace the maps of the body material. A map you leave out keeps the base’s.
portrait replaces the select-screen and in-run portraits. It is the riskiest field: a UI texture under a new name once hung level load (a POI minimap icon), so try it separately.
weapons gives a weapon its own mesh (model, a static mesh) and/or maps (albedo, mra, normal). Only this hero carries it; the base keeps its own. The mesh is used exactly as authored, in the weapon’s own space: export it ON ITS OWN with its object transform cleared, not while it is parented to the hand bone of an export-character file (the cooker bakes object transforms, so a weapon exported in the hand ends up offset).
animations cooks each clip under a new name (Nyx_Piper_Dash_Default) and points only this hero’s entities at it. The animation kind replaces a clip for everyone who plays it; this does not. Keys are the base’s clip names, as rsmm export-character prints them. A .glb path alone means the action carries the clip’s own name.
outfits are more skins, each with its own name on the skin page. An outfit is the Default look wearing its own body maps, and with model it gets a body of its own too, rigged like model (to the base’s skeleton). Outfits take the skin slots after Default in order, and the slots after them show Default. They may show as locked: the base’s skin unlocks do not carry over to a new hero.
values sets the hero’s numbers: cooldowns, durations, radii, damage multipliers, pet counts, projectile lifetimes. rsmm export-character <Base> --list-values lists what can be set and in which entity. A bare label sets it everywhere; <Entity>/<Label> sets it in one entity only. A misspelt label fails the build.
references swaps anything the hero’s own entities name: another VFX, a sound event, a mesh, a clip. Each new resource’s preloads are borrowed from a shipped cache that already loads it. A resource no shipped cache lists is refused, because an unlisted preload crashes the game at load.
skills gives the hero talent and ability cards of her own: [content.skills."Dash Trap"] (a talent, as its Skill Controller names it) or [content.skills."Ability Power"] (an ability slot), each with name and/or description. The base hero keeps his cards. The number of talents is fixed, so this relabels a slot; change what the talent does with abilities (its parts are the Skill <talent> group). Keep the card’s {N} placeholders and #…@ keywords: the numbers come from the card’s own String Format.
placeholder (a PNG, a flat pink by convention) paints every piece of art the hero still borrows from its base: each character material (body, gear, companion, every skin), every ability and talent icon, the HUD images, and the book’s portraits, skin icons and codex pictures. Whatever is still pink in game is what is left to make. albedo, weapons and portrait win over it. Story pages the hero does not write itself read as pages still to write.
effects gives the hero particle effects of its own. Every effect in the base’s own FX folder (Beowulf has 99) is copied under the hero’s name with its own materials and textures, recoloured to a tint at each colour’s own brightness, so shapes and transparency stay. The recolour reaches the colour textures (never masks or surface data), the materials’ colours and the effect’s own colour ramps, which are what make fire orange: [content.effects."*"] tint = "#7ad0ff" for all of them, or [content.effects.Beowulf_Shockwave_Front_01] for one. With placeholder, effects given no tint turn pink. Effects shared with every hero (Common_FX) are never touched.
hide lists meshes the hero does not have, by name ("Wyrm_GEO", Beowulf’s dragon) or full path. Each is swapped, in this hero’s entities only, for an invisible copy: the same mesh on the same skeleton, shrunk to about a thousandth. Everything attached to its bones keeps working, so the dragon’s fire still comes, just from nowhere visible. Its sounds stay.
memoirs is the book’s story pages, in order: [[content.memoirs]] tables with title and text (Beowulf has 7). A page left out keeps the base hero’s story, or shows a placeholder when placeholder is set. The narration audio stays the base’s.
abilities edits how her abilities are wired. An ability is a graph of parts (states, timers, tests, spawners, values) inside the hero’s entity; rsmm entity-graph Piper --group "Ability Secondary" lists one ability’s parts and links, and --show "<part>" shows a part’s fields by name. Each step is one of:
- clone = "<group>" + as = "<new group>" (or clone = ["part", ...]): copy the parts under new names (suffix, default " " + as). Links among the copies point at the copies; everything they own is copied too. from = "Juliet" copies from another hero.
- set = "Part.field" + value: a number, a bool, or [x, y, z]. "Part.field[n]" sets the n-th number (or [x, y, z]) inside an object field, as --show prints them; with a text value it replaces the n-th string instead, e.g. set = "My Spawner.template[1]" with value = "Heroes\\Hero_Beowulf\\Hero_Beowulf_Shockwave.entity.ot" makes a spawner spawn something else.
- link = "Part.field" + to = "Other Part" ("" for nothing); a list element is "Part.list[0]", and "Part.obj[n]" is the n-th reference inside an object field (--tokens lists them, empty ones included).
  
  Turning a spawn. A spawner’s own yaw fields (position[8], transform[5]) are ignored for a hero’s ability spawn: four shockwaves turned that way all went the way the hero faced. The game turns a spawn the way Piper fans her notes: the spawner reads a 3D node, whose Y angle (radians) comes from a value. Copy a spawner together with its node (clone = ["Attack Shoot Projectile Spawner 02", "Attack Shoot 3d Node 02"]) and point the node’s angle at a value of your own (link = "Attack Shoot 3d Node 02 Copy.obj_4[5]").
- add_link = "Part.list" + to, and remove_link = "Part.list[i]". Add entity = "FX" to a step to edit another entity of the family. The Abilities tab of rsmm editor builds these steps for you. It opens on Numbers: every number the chosen ability uses, by name (type a value, press Enter; ↺ resets it). The Diagram tab draws the ability as a graph of parts for re-pointing links and copying groups. Every change is re-checked straight away; press Copy manifest code and paste it into the manifest. Every edit is checked before anything is written, and the build fails rather than install an ability that cannot work: a link into an entity the hero does not carry (copying Juliet’s secondary drags links into Hero_Romeo_Juliet_Common, which a hero built on Piper does not have), a part left owning nothing, a number re-pointed at a value of another type. The check proves the wiring is sound, not that the ability plays the way you meant: that is still a playtest.
[[content.attacks]]: an attack of the hero’s own that replaces an ability slot, declared instead of wired step by step:
```
[[content.attacks]]
id        = "Crescent"             # its entity is Hero_<hero>_Crescent
slot      = "special"
model     = "art/crescent.glb"     # static mesh, glTF +Y = direction of flight
albedo    = "art/crescent_alb.png" # mra / normal optional
speed     = 16
lifetime  = 0.9                    # seconds
beats     = [[0, 180], [90, -90]]  # each beat's angles, 0 = where the hero faces
delay     = 0.4                    # seconds between beats
animation = "art/cast.glb"         # replaces the slot's clip (`clip` = its name)
```
The projectile is a new entity of the hero’s own on the engine’s generic hero projectile (physics, hits, piercing, damage and despawn come from it), with the mod’s mesh and maps, the hero’s own trail and impact effects (tinted by effects) and the base’s projectile sounds. Each angle fires from a copy of the base’s projectile spawner and 3D node, turned by the node’s angle (see Turning a spawn above). Beat 0 fires when the slot is used and each later beat on a timer inside the slot’s state, so the slot’s animation must last until the last beat. Damage is the generic projectile’s for now. Supported bases so far: Piper (slot = "special").
own_entity = true is implied by every field above except name, description and portrait. The hero gets its own gameplay entity: every Hero_<Base>* entity (the hero, FX, pets, projectiles, skins) is cloned as Hero_<id>* with its paths and scopes renamed, and a new alias in ApplicationSettings.ot binds the skins to it. The whole family has to move together, because a pet or a projectile reads its owner’s values by the owner’s template name. With its own entity, the hero’s abilities and values are its own to change later.

Prove it. A portrait named after your hero, your body and texture when you pick it, and the base’s abilities (Piper’s rats and notes) working in a run. How the pieces connect is written up in docs/_re/kinds/heroes.md under “How a hero is assembled from data”.

Where to go next

Content kinds & confidence — the generated rating table, and the only place a rating is written down for readers.
Authoring mods — the full manifest surface, patches, merges, load order.
Conventions & best practices — naming, pre-flight checklist, surviving game updates.
Example mods — complete mods that ship in the repo.

First mod, by kind

The loop, every time

item — a new magical object

talent — retune a talent

ability — change a shipped hero’s abilities in place

entity — edit any shipped entity in place

mesh — put your model in the game

animation — replace a clip with your own motion

poi — a structure in a chapter

enemy — change what a camp spawns

reward — ban or retune what spawns at reward points

shop — change the Sandman’s stock and prices

tilegen — a chapter’s map-generation recipe

game_mode — reorder the chapters of a run

map — make a chapter play a cloned map

skill — relabel a talent

modifier — a custom run mutator

melody — retune one of the Piper’s melodies

boss — make a boss arena fight another boss

hero — add a hero to the roster