Kror is the only boss in the Deeplands. He is one of the most powerful bosses in Advent of Ascension. Kror is spawned by using a Boulder Dash on a Kror Altar, which is found on a Kror Pillar.
Kror is immune to knockback. He will occasionally attempt to pull you towards him and inflicts the instant damage effect on you when near him, meaning you will die almost instantly (with the exception of a few armor sets if you are wearing them) if you get in physical contact with Kror. All projectiles that hit Kror are capped to doing a max of 10 (×5) damage.
WARNING: If you do get in physical contact with Kror and he himself had the chance to hit you, not only will it do a lot of damage but inflict Slowness III for 7.5 seconds, making it impossible to escape the instant damage radius.