Focalor is the second boss in Bloodstained: Curse of the Moon.
Origins
Focalor is a powerful Great Duke of Hell, commanding three or thirty legions of spirits. Focalor is mentioned in the Lesser Key of Solomon as the forty-first of the 72 goetic demons. According to the grimoire: Focalor appears in the form of a man with a griffin's wings, kills men, drowns them, and overthrows warships; but if commanded by the conjurer he will not harm any man or thing. Focalor has power over wind and sea, and had hoped to return to heaven after one thousand years, but he was deceived in his hope. One of the three archdemons, Lucifuge Rofocale, has his second name as an anagram of Focalor, implying an intellectual relationship.
Description
Found at the end of the frozen cavern in the appropriately named Frigid Hell. Focalor is a flying, merman-like creature with a humanoid, yet monstrous-looking head and torso, and a turtle-like shell and fins from the waist down.
He mainly attacks by shooting streams of fast-traveling bubbles from his hands. He can also conceal his upper body inside his shell and dash at great speed across the room. Another of his attacks consist in him summoning a ring of bubbles that will start spinning around him while he floats about in an undulating manner, in an attempt to inflict physical damage with the player. These bubbles can be destroyed with a single hit from most weapons, leaving Focalor vulnerable until he finishes the attack; otherwise, he will eventually send them out in a spreading manner.
There are three icicles hanging from the ceiling which will fall down and encrust into the ground when Focalor is preparing his rushing attack. These can be used to step onto in order to have a better chance of jumping over him while he is rushing across the floor. Afterward, ice boulders will start falling from the ceiling, indicating the spot from where he will reemerge. After three sets of these boulders fall off, he will quickly drop from the top in an attempt to crush the player.
Once his health has been depleted, Focalor will perform one final attack in a last ditch effort to harm the player, where he will momentarily exit the screen and then make one final dash across the room while engulfed in what appears to be a giant water wave, crashing onto the wall and obliterating his body in the process. To evade it, either jump to lure his attack to pass above and miss, or hit him as he comes by to misdirect the attack.