His divine robes give him 100% immunity to all fire based attacks in the volume 1. And if you are talking about speed feats, then it is same for the Zoldycks. And no, Cheetu is not Mach 21. It is totally baseless and fan wanks, but if you want to believe it so hard, then it your thing. Now about Nanika, you are partially right. But the question is how? Ainz is an undead, not a living being. You can't hurt him without magic or supernatural level at the level of Shalltear. Also, Reality Warping is pretty common. Though the question remains, what is your wish? Teleport him somewhere? Ainz has teleportation immunity. Kill him? But what? He is already dead. Also, what city level? Killua never blew up a building, nor Zeno and other characters. And if you are talking about nukes, what you will nuke? Ainz is totally immune to fire itself. And before putting my post as a wrong here, you should be more polite. Don't be arrogant, okay?