Forbidden Tiers extends Iron's Spellbooks by re-enabling two spell rarities that were always present in ISS's code but never used: Mythic and Ancient. Every spell automatically gains additional levels for these tiers based on its configured max level, so spells with less levels gain fewer extra levels than the ones with more.

Because the mod works by hooking into the spell system directly rather than targeting specific spells, it has automatic compatibility with every spell in the game — ISS's own spells, addon spells, all of them. No extra patches needed.

All existing config options like max level and min rarity are still fully respected, and the new tiers are added on top following the same rarity curve logic. Two new Inks have been added which are obtained the same way as you obtained the base ISS inks. Check JEI for detail.

Modpack authors can also use the forbidden_tiers:mythic_blacklist and forbidden_tiers:ancient_blacklist datapack tags to suppress the new rarities on specific spells if needed.

Credits

Huge thanks to Logar for creating the texture for the two new Inks

Licensing Notice: This mod uses a Split License.

Code: LGPL-2.1 (Open Source)
Assets (Sprites/Models): All Rights Reserved. You are permitted to fork or port the code, but you may not use the original textures or art assets in any public versions/ports without my express permission.

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