How do i kill the cyclops the cursed mine in multiplayer?

[Rogdor_345]

I usually play MP alone...my char's level is high enough to deal with a horde of pesky groms :P when i went to door,it said i had to kill all of the groms to enter the "radiant champion's" room. "a glowing grom? pretty easy". oh man. once i entered the room,i saw what the radiant champion was; A GIANT FREAKING CYCLOPS. yeah,i've slayed many Cyclopses in SP but in MP,this guy was just plain tough. he is resistant to everything and he has a large amount of hp. his hp bar doesn't even decrease that much when i hit him. what should i do?
is it because my character is too low-leveled? (level 7?)

[Voxsound]

you need to kill whatever else is in the room first to be able to do damage on that thing? (maybe xD)