Spell Engine Extension (RPG Series Tweaks)
by TheRedBrain
Spell Engine Extension is a Fabric add-on for the Spell Engine mod that adds costs, schools and attribute-driven spell tweaks, and it is released under the MIT License.
What it does
Spell Engine Extension sits on top of Spell Engine and changes how spells are cast. Casting can be limited by what a player holds in hand, and spells can cost health, mana or stamina. Mana costs draw on the Mana Attributes mod and stamina costs on Stamina Attributes, and both are optional, so a world without them still loads the core features.
The mod adds three generic spell schools, melee, ranged and magic, and nine entity attributes that shape how a spell behaves, such as projectile count and bounce amount. Several config options control the spell hotbar, and a few smaller optional tweaks are included. The mod does not alter vanilla game data; instead it gives data pack authors more options when designing spells.
Installation requires Fabric API, Fzzy Config and Spell Engine. The client and server both need the mod, and files are published for 1.20.1 and 1.21.1, with 2.17.2 for 1.21.1 as the latest build. The source code and issue tracker are public.
Key features
Hand-limited casting
Individual items can restrict which spells a player may cast depending on what is held in hand.
Health-cost spells
Spells can be configured to spend health instead of a resource, giving casting a direct cost.
Attribute-driven spells
Nine entity attributes adjust cast spells, for example by changing projectile count or bounce amount.
Spell hotbar options
Config options customize the spell hotbar layout and behavior on the client.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 3
Optional 5
Use cases
Data pack spell design
Pack authors can combine the schools and attributes to build new spells without changing the game's own data.
Who it’s for: Players and server owners who run Spell Engine and want costs, schools and attribute tweaks, and data pack authors designing spells on Fabric.
How it compares
More RPG Library is a Fabric, Forge and NeoForge library for 1.20.1 – 1.21.1 under the MIT License, open source. Spell Power Attributes covers Fabric, Forge and NeoForge across 1.19 – 26.3 under the GNU Lesser General Public License v3.0 only, also open source. Invocations is Fabric-only, open source under the MIT License, and targets 1.20.1 – 1.21.1 as well, so it fits the same Fabric setup.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Spell Engine Extension (RPG Series Tweaks) | Fabric | 1.20.1 – 1.21.1 | Client and server | 2026-09-29 |
| More RPG Library | Fabric, Forge and NeoForge | 1.20.1 – 1.21.1 | Client and server | 2026-10-11 |
| Spell Power Attributes | Fabric, Forge and NeoForge | 1.19 – 26.3 | Client and server | 2026-09-28 |
| Invocations | Fabric | 1.20.1 – 1.21.1 | Client and server | 2025-01-27 |
Questions
Does Spell Extension require Spell Engine?
Do players and servers both need the mod?
Are Mana Attributes and Stamina Attributes required?
In the catalog
Spell Engine Extension (RPG Series Tweaks) is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 32,366 mods support Minecraft 1.21.1.
More from TheRedBrain
Similar mods
What the author says
This is an extension to the Spell Engine mod by Daedelus. On its own it changes nothing in the game, but mod and data pack authors have more possibilities when designing spells.
Official listing
- Modrinth page
- modrinth.com/mod/spell-engine-extension
- Owner
- TheRedBrain
- Published
- 2024-05-06
- Updated on Modrinth
- 2026-09-29
- Facts verified
- 2026-10-15