Deepcraft: The Nether Fortress

The dungeon doesn't end at the bottom of the Overworld — it keeps going, straight into the Nether, with no portal and no loading screen. Jax, Mugs, and Kael drop into a corrupted fortress of blackstone and lava where the heat never lets up and the mobs fight like soldiers: blazes that volley in formation, ghasts in corridors too tight to dodge, wither skeletons holding the chokepoints. Then the floor splits the party in two, and for the first time they have to survive apart — each trusting the half of the plan they can't see. When a book in the loot starts writing itself in a language no one can read, one thing becomes clear: this dungeon wasn't generated. It was authored. Someone built this on purpose, and they've been watching the whole time. Below the fortress waits endstone. One zone left.