Does anyone know the level you need to be to complete this quest? Most of the guides I'm seeing say 12-14, but now being level 16 I still can't seem to get it.

I went back and made sure of the following:
First part of killing the imp leaders is completed. (The imp leaders call me imp slayer)
The ordinary ring has already been turned in
Troll King was terminated and I was given the 7p Dragon Claw
Killed the Barbarian Lord, but I still see the quest. However I can't get the drop again.
Rog and Thoran both show up as completed in my Task UI (Killed them again to make sure) and I have received the Vis Animus Ring.
Killed Ixereic and Jaws again to make sure, that part is completed.
Can't get the quest to kill Sath.

Any help would be appreciated, thank you. Here is the link I was using: http://xenheroes.weebly.com/chain-quest.html

Edit: 17 and still cannot get the quest. May just be a level thing.

I've never actually "got" the quest ahead of time. The order I do my noob quests is as follows:

Imps
Jorn
Troll king
Barb Lord (server and ds barb lord both work find but ds is much easier)
Rog
Thoran
*Get ring*
Ixereic and Jaws
Sath

When doing Sath I just go and get the kill/his head or w/e and then turn into Synax for reward. *Note - I have had this quest fail multiple times when he would start talking to me and then go off to kill a bug and I wouldn't get reward. I make sure to kill all enemies nearby before turning in now.

At level 16 the quest guy tells me to come back when stronger, so it's definetly a level thing. Not sure what level though.

I didn't know it had a level requirement on it. Guess you'll have to try each level