I recently went into the nether and found loads and loads of wither skeletons spawning, but after I killed them all they stopped spawning altogether. Why is this? This is occurring in the Xbox One version.
There are three (3) requirements for a Wither Skeleton to spawn:
- Light levels must be 7 or less
- Must be on Nether Fortress (on nether bricks and their variants)
- Must have 3 blocks of vertical space (wither skeletons are 2.5 blocks tall)
In other words, be sure to hang around dark Nether Fortress with plenty of head room.
You'll just have to reset your nether to get the wither skeletons to spawn again, I find once you've entered the nether, left, and came back they stop spawning. I'm on my seventh beacon and I've had to reset the nether who knows how many times.