Witherlands

A new nether biome with fortresses/bastions/ruinedportals. It’s called the witherlands. Every second, there is a .0009% Chance for a wither skeleton to spawn, and every second there is a .00001% chance for a wither to spawn. Blazes/ghasts have the same spawnrate as the wither skeletons. The ground is soul sand/lava/bones/Ancient debris. Every block has these chances:
80% Soul sand

10% lava

9.8% bones

.2% Ancient Debris