Slay the Spire Modding on OpenMods

A deckbuilder with a deep mod scene on ModTheSpire

Slay the Spire (2017) is Mega Crit's roguelike deckbuilder. The modding architecture is layered Java + Lua via ModTheSpire and BaseMod, community frameworks that hook the game's JVM runtime and expose APIs for custom cards, characters, relics, events.

The catalogue is remarkable for its depth: dozens of custom playable characters (each with their own card pool, Marisa Kirisame, the Bard, the Hubris collective), gameplay overhauls (Hubris, Replay The Spire), and quality-of-life utilities. Most STS modders work in Java.

The toolchain

• ModTheSpire: the foundational mod loader. Hooks the JVM, loads .jar mods.
• BaseMod: framework layer on top of ModTheSpire. Provides utility APIs.
• StSLib: additional shared utilities.
• Manual install: drop .jar mods into the mods/ folder under your STS install.

What you'll find on OpenMods

STS mods live primarily on Steam Workshop and the STS modding Discord. GitHub hosts source for many mods (Java-based development workflow). OpenMods catalogues GitHub-published STS mods.

Practical notes

• Workshop subscriptions auto-install. STS uses Workshop natively.
• Mod compatibility is usually good. ModTheSpire's API has been stable; most popular mods coexist.
• New characters are the headline. "Add a new character with X cards and Y mechanic" is the canonical STS mod type.
• Save game compatibility. Runs (a single playthrough) are mod-specific. Removing mods between runs is fine; mid-run is not.