How To Beat "the Beast"?

I am a level 58 Assassin and I am getting destroyed by "The Beast" in the Prison of Souls alter. I have one set of armor that gives me 1915 health, good elemental defense, and a lot of Thunder Damage. I have another set of armor that gives me 3205 health, bad elemental defense, and a lot of Poison and Life-Steal. And I can't beat him with either set. Is there a certain way I should kill him and the others? Or do I just have to keep trying until I beat him? I want the Marius' Prison chest plate so I can improve on my Poison/Life-Steal Set. But I can't beat "The Beast". And it sucks too. Because I heard that the only way to get Marius' Prison is the beat "The Beast".

 

You can beat it with the power of DETERMINATION.










No but seriously I can help you with the altar if you want, my IGN is Arnold102, feel free to msg me ingame when you want to do it

 

I don't know if your still on but I tried to message you and it said you weren't online.

 

He isnt pnline 24/7 you know

 

OH REALLY?!?! I thought he was a robot that never got tired! You're telling me he is a HUMAN!!!!!! :OOOOOOOOOOOOOOOO

I messaged him literally 5 minutes after he replied and it said he wasn't online. I tried to message him multiple times every 30 minutes for about 3 hours. I finally gave up. I played for another hour and then replied told him what it said when I tried to message him.