When fighting bosses and high levels there is a simple way to beat it, most the time without getting hurt.
Very simple really, surround the enemy with 3 people (like a triangle) Make sure your out of its hitting range. Then 1 player hits the enemy with an ability, then a second player hits it with an ability, then a 3rd person hits with an ability.
TimingEditIts important that you time your hits. After the first player hits the monster the 2nd player should wait a moment or 2 before he hits the monster. Same thing for the 3rd player. If you wait to long the monster could kill a player, if you do it to fast you get out of sync and could get yourself killed.
Pictures to detail the method, the caption explains the scene.
Warning: Only hit the enemy once or it throw off the cycle, do not hit the enemy out of turn or it will ruin the cycle.