Why is he called mad?
He looks same as all other dragon priests to me.

More info on Otar here: http://elderscrolls.wikia.com/wiki/Otar_the_Mad

Here's more at UESP but it has spoilers on the related quest, so proceed with caution: http://www.uesp.net/wiki/Skyrim:Ragnvald_(quest)

Otar has popped out of his crypt before I used the keys on it when I put down a Lightning Rune near it. Otar has hidden when his health was low and all I could hear was his heavy breathing but I couldn't see him. Otar has been on the other side of the door out of his crypt when I was just going to enter the chamber where he was. That was all pretty insane on various visits to that dungeon and no other dragon priest did those things with me. I have no idea about his history though. Good luck with him!

still doesn't say why he's mad, and i have already beaten the quest and found Konahrik

Due to voices in his head? Pretty sure I read that within 10 seconds of clicking the second link.

http://www.uesp.net/wiki/Skyrim:The_Secrets_of_Ragnvald

Here's a book that doesn't appear in-game but explains more of Otar's madness.

um...

Yes, that. Unless the OP is confusing "Otar, you mad?" with "Otar, you crazy!"


I saw that at one of the links I posted. And just because of that, I'm including it in the player house mod I'm working on right now.