Arcanite Bars & Transmutation Mastery

[Lissa]

It's also possible (but would be fun to find out) that he just does what the servants in the blasted lands do. Simply become unkillable. I skill weapons on those guys if I have a good way to self heal because you can beat on them all day long. And it is possible to get them to far from the crystal so that you can't you break that to kill them either and they will not die. I remember one being kited to IF and he had hundreds of folks beating on him and he couldn't be killed. Since you need domo alive to get Rags he could be unkillable.

It's also possible (and I would like to find out as well) that you can beat him low enough to make him submit and the guards just go away.

This is my thought as well. Also, unlike the servants, I bet he'd be more like Golmagg's dogs that heal back to full when they reach 50%. I also seem to recall that damage I was doing was very, very limited from looking at the combat logs (like he had a 95% damage reduction) cause the off tank that wrangles Domo has a very hard time building rage because you just aren't doing any damage to build the rage to do aggro producing moves (unlike the the person that has active control of him at the time).