Old man 12 temple quest: can't pass level 30

So I made it to lvl30 of the 12 house quest (the one that you get from the old man close to the vendors for the cloth); which required 40K power, but I can't beat that blue enemy.
I am 72, he is 60; no matter what; even if I avoid his attacks (when the red cone is displayed on the ground), I still get hit at random and loose half of my health.

I tried to run around, but then it seems that there is a time limit, so if you don't kill the guy in a certian amount of time, you loose it anyway.

Is there a specific way to win that fight? To me it seems either bugged or there is something that I am missing....I never had to fight any enemy so far, for more than one or 2 times; but this guy already killed me 6 times.

I believe that this is also the quest so I can get my first silver cloth...but I am 10 level higher than him and still I get hit once (without any red cone on the ground, so can't avoid it), and loose half health. Potions still won't do anything.

Suggestions? Is there a specific trick for this guy? Do I have to be 80 to beat him? My tier 2 bronze is at max level; really not sure what else I need to do to kill the guy.

Problem solved: The cosmo requirement is higher than what I had, so I could not pass the level.

Once I did upgrade my equipment and improved power, then I was able to go on and finish the floor.