Does anyone know if Durnehviir will respawn more than once, because the second time I saw him I decided to go for a sneak attack with my bow because I figured the only good dragon is a dead one. Now it seems this is not the case and I will need him to acquire certain shouts.

Same happened to me, let me know if you find a solution.

So you said you killed him? Or when you first shouted for him he came a flew away? If its the second one just shout again at the floor and he'll appear and tell you the next word

No, we just weren't able to get Summon Durnehviir at all because we killed him before he could start dialogue outside of the Bone Yard after recieving the Elder Scroll.

I have the same problem, and browsing around the interwebz I saw that lots of other people did too. I read a rummor that someone found him sitting on a broken dragon shout wall in the Soul Cairn, but I have yet to find this wall. I'm sure I've seen it before, but the place is so big I can't remember where it was.....

It's to the left of the entrance to the castle. It doesn't do anything though.

It's not a rumor it's true, you can find him sitting on a broken dragon shout wall in the Soul Carin. I believe from where the entrance is and looking at the castle or wherever Serana's mother is in the Soul carin, go past the gate thing and go all the way to the left and he should be in a broken looking building sitting on the wall. He can never die as he gets reformed back into the soul carin

Yeah but he's talking about where to find the dragon, which is on the broken dragon shout wall

Thanks for the tip, I found the wall but he's not there. Do you know if there is an amount of in game time I have to wait for him to respawn, and if it has to be done within the Soul Carin?

He doesn't respawn, it's yet to be fixed, don't believe rumors about some word walls and that.
That't what you get for being prejudiced, would you say the same for Odahviing or Paarthurnax?

It's not a rumor if you don't kill him the second time when he tries to talk to you and ask a favor.

He still wasn't on the wall for me . Anyone have progress on this yet?

So you guys killed him when he was talking to you after the first battle with him?

Yep.

Raxos:

Well, in our defense we had no way of knowing he'd give the shout to us. When you first meet Odahviing he's unkillable. And you are told by the Greybeards that Paarthurnax is their leader, so different conditions. Here, Valerica just says that she wouldn't be surprised if he came back and then bam, he respawns. Not really much of a warning......