You are in a maze with 4 - 6 boss Siphos. Each one aimlessly wander around until you are in their line of sight, where the one that sees you would chase after you. You have to maneuver the maze and not be seen by them, they can only see from their front side. You can safely attack them from the sides and easily kill them that way, but doing so will make all others seek to where the kill was, so you have to be careful.This kind of boss behaviour which is also arena-layout dependant should encourage players to take more cautious fights. Sneaking up on the boss and hiding from other bosses after a kill should make a nice pace-changing challenge. Congratulations!
When you wither it down to around 3 or 2 left, the rest will flee into a whirl pool and you win the fight.
You should not attack form the front side of them.