Like the Castle Boss, the Submarine Shrine Boss has ridiculously huge LP and two attacks: a triple Fire attack with low damage but a huge range, and a Flake attack (with less range) which can home in on characters and freezes them for 5 seconds upon contact. A good strategy would be to use the Dodge strategy with a Sniper with a Triple Poison 4. Another good way to kill it is by dragging melee characters directly to the boss's head so that it is close enough to it to not get hit by the Flake or Fire attacks, while the ranged characters add more damage to it. Cornering it so that it will not move allows extra damage to be given. The Flake attack's effect can also stack, but since the attack is weak, the characters have a somewhat decent chance of escaping if another character draws the boss