I must say I was not sure what kind of a pet he would turn out to be...he doesn't have any extra skills...check him out..

http://petopia.brashendeavors.net/html/mobs/mob_zarakh.shtml

but ...
If any warlocks are out there he is very similar to the VW he tanks and does it well....
Armor at lvl 23 is like 2000
Resistance 30 in arcane, fire, nature, frost, and shadow is in the 40s
an unbelievable pet 
I can take on a warlock with a VW no problem.
the only thing that hinders this pet is if he falls asleep..... HE EATS ALOT!!!! Make sure he is well fed lots of meat he will eat certain types of raw meats, but can and will eat any type of meat we eat.