The LEVIATHAN is often considered the boss of the game. It is a massive, towering fortress that spawns in the center of the arena. It rotates slowly, but otherwise does not move. The LEVIATHAN does not actively attack the player, but instead consumes the SKULLS around it in waves, and releases them again in a much stronger possessed form.
Upon death, the LEVIATHAN leaves behind a crimson ORB. The ORB behaves much the same was as the LEVIATHAN, drawing SKULLS to itself; the ORB does so more frequently, every three seconds, but this timer is paused so long as the ORB is taking damage.