Golemagg the Incinerator in Molten Core soloed by an affliction warlock.
Standard PvE-Buid 56/0/15 , lvl270+ gear.
Pretty simple fight, draintank the adds, don't let them get the buff.
after vw build up some aggro start dps slowly, you will need to soulshatter since you dont have talents in demotree to improve pets threat.
I used warlock t5 2pc bonus, since i dont have pethealtalens either.
Fightduration ~ 8minutes, vid at 2x speed.
edit: after some testing it turned out, that tanking the boss by yourself and letting vw tank both adds is much better idea. just need to watch out the earthquake at 10%, it hits pretty hard. best solution would be, renew all dots at 12-14%, pop voidwalker shield and ds him to death since you dont get interrupted while its up.