I'm a 36th lvl Necro on the Saryn server and I solo these all the time. Hit it with Dooming Darkness, then Invoke Fear, send pet, then VoS, Boil Blood and Vampiric Embrace, fear again if need be, then for added measure I hit it with Torbas Acid Blast. When the Dooming Darkness fails, I usually send the pet, let it take the agro, then cast again, when it takes, fear, dot, rinse, repeat. If everything fails, FD and let the pet die, wait and run, med, and recast pet then try again. Most of the time I can take a yellow /con but I did try a red and he smacked me down (resisted everything I had). Hope this helps...
Zdatil
36th Gnome Necromancer
Saryn Server