Chimera Core - Creature Genetics, Breeding & Evolution for RPG Maker MZ

Your capture plugin gets the creature. Then what?

You've built the capture system. The player throws the thing, the bar shakes, the creature joins the party. It works.

And then a playtester asks the question that sinks the whole project:

"Why would I ever catch a second one?"

Because there's no reason to. Every creature of a species is identical. There's nothing to breed for, nothing to hunt for, nowhere to put them, and nothing to chase after level 20.

Capture is the first ten minutes. Chimera Core is the next hundred hours.

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What it does

Genetics — no two creatures are ever the same

Eight hidden stat genes, 25 natures, gender, ability slots, and rare variants. Two level-5 creatures of the same species now have measurably different stats — so the player has a reason to catch the second one, and the twentieth.

Breeding — the reason to keep playing

Real parental inheritance. Genes pass down from both parents, natures can be inherited, mutations happen, egg groups gate which species are compatible, and eggs hatch as the party walks. Breeding generation is tracked, so players can see their lineage depth and chase a perfect specimen across generations.

Evolution — branching, not a straight line

A full condition graph, not a level check. Evolve on level, item, friendship, time of day, gender, variant status, trade — or on stat comparison, so the same species becomes one creature if it grew strong and a different one if it grew tough. Stack conditions freely. Genetics, training, friendship and nickname all survive evolution.

Storage — built for a real collection

Multi-box PC storage with sort, search, and filter. Find every variant you own, or every creature above 80% genetic potential, instantly. Default 24 boxes x 30 slots = 720 creatures — and it does not slow down when full.

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Built to stay out of your frame budget

Most collection systems fall apart exactly when the player finally has a collection. This one doesn't.

Genomes are bit-packed into two integers instead of objects. Computed stats are cached behind a dirty flag. Box drawing is paged, so cost scales with what's on screen, not what's stored.

Measured inside RPG Maker MZ — real corescript, real PIXI WebGL rendering, with 600 creatures stored and the storage scene open:

• 2.6 ms per frame with normal cursor movement — 15.7% of the 60 FPS budget
• 2.8 ms even when hammered at 60 cursor moves per second, about 8x faster than a human can press a key
• 61 bytes per creature in the save file (43 KB for a full 720)
• 0.655 bytes allocated per frame — effectively garbage-free scrolling

That leaves roughly 80% of every frame for your game. And the fact that abusing the UI barely changes the number is the real point: storage is not where your frames will go.

The benchmark ships with the plugin. Run it yourself.

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Works with your capture plugin, not instead of it

Chimera Core deliberately does not implement capture. You've already solved that, or bought a plugin that did. Chimera sits on top of whatever you're using and adds the layer none of them have.

Drop it in below your capture plugin. Nothing else changes.

• Compatible with existing capture plugins
• Compatible with VisuStella MZ
• Compatible with battle system replacements — Chimera touches no battle code
• Safe to add to an existing save
• Zero dependencies

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Source you can actually read

Ships uncompressed and fully commented, with JSDoc on every public function. Never minified, never obfuscated.

You're buying an engine mechanic, not a black box. When you need to change how inheritance works at 2am three months from now, you'll be able to find it and change it. Over 1,100 lines of documented, auditable JavaScript, plus a 40-test suite so you can verify any change you make didn't break anything.

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What's in the box

• ChimeraCore.js — the complete engine, uncompressed
• ChimeraStorageUI.js — optional storage box scene
• Full user manual with API reference, recipes, and troubleshooting
• 40-test headless verification suite
• Performance benchmark you can run yourself
• Commercial licence — unlimited games, zero royalties, forever

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Licence

Use it in unlimited commercial and non-commercial games, forever, with no royalties. Modify it freely for your own projects. You just can't resell the plugin itself. Full terms in LICENSE.txt.

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Requirements

RPG Maker MZ. No other plugins required. No dependencies.

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Now available — Chimera Battle

You bred for a +Attack nature. Chimera Battle is where it finally matters.

A real type chart with a live effectiveness preview, move sets with their own PP, status effects with stat stages and type immunity, and an opponent AI that reads the matchup instead of picking the biggest number. Chimera Core's IVs, training and natures feed straight into its damage formula, so two creatures of the same species at the same level hit for genuinely different amounts.

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The rest of the Chimera line — all three now available

Chimera Battle — type chart, move sets with real PP, status effects with stat stages, and an AI that reads the matchup.

Chimera Field — biome spawn tables, rarity tiers, level bands, variant rates and a Field Guide that records where each creature lives.

Chronicle Core — branching quests, choices that foreclose, faction reputation & world state

Each is an independent plugin that runs alone. Together they share the same <chimera species: N> notetag, so a project tagged for one is tagged for all.

Get all three in the Chimera Suite bundle →