JJThunder King of the Hills

Transforms Terrathunder_1.18.2_v0.1(Fabric) into forge with enabled seedfix in both overworld and nether.

Note: Terrathunder_1.18.2_v0.2 is around the corner, with many bugfixes and terrain/biome changes and balances, in addition to overground rivers blending with underground ones. Will not focus on caves, nether, and terrathunder biomes revamp though as they will be left to another future update.