The main problem with fighting General Rajaxx is that you aren't just fighting General Rajaxx. Before you can engage Rajaxx, you must fight your way through seven waves of his troops, each wave lead by one of his captains, majors, and colonels. (Each wave consisting of one leader and six troops of various types.) After fighting through all of this you get to meet the General himself, who's no slouch.
The General is a meleer whose most dangerous ability is an AoE Thunder Clap which knocks everyone back, drops aggro, and cuts their health in half. So if you have 6000hp when you start the fight? Now you have 3000hp. And after the next Thunder Clap, you have 1500hp. See the problem here?
When you engage Bloodlord Mandokir, you fight Mandokir and his raptor, Oghan. If you kill Oghan, Mandokir will enrage for a period of time -- and the additional damage done while enraged is usually quite sufficient to end the attempt.
In a fight, Mandokir relies on powerful melee abilities to defeat his opponents. He hits hard, has a dangerous AOE whirlwind attack, and will occasionally charge at the target farthest away from him. Occasionally, he will pick one of his opponents to "watch." While he's "watching" a target, if that target does anything to cause threat (healing, DPSing, etc), Mandokir will immediately charge the target, causing massive damage.
Oh, and if you die? Mandokir gains a level. (And just like players do, he'll yell "Ding!")
For the fight itself, we're presuming these two bosses would be of the same level and, approximately, the same health and damage output. They're fighting on neutral ground, so the NPCs that help you with Rajaxx and the rezzing ghosts around Mandokir are out of the picture. So if these two clashed, who do you think would come out on top? Obviously, if Mandokir fought through the waves of beasts coming in before Rajaxx, he'd have a serious advantage -- having gained nearly 50 levels. But would he make it that far, or would Rajaxx's swarms overwhelm him?
Voting is closed and this week's fight is finished -- but you can still check out the results