Go up close and slash him, or just get close to him. He should either attack you with his freeze punch then run, get on snowboard and attack you, or will use a bird freeze attack that launches iceballs at you. To counter the first one, run backward then attack. To counter the second attack, jump over the board two or three times then try to attack. To counter his third attack, move backward then slash the snowballs. Note: You will have to do this at least once during the attack. Also, when he gets on his board and ice spikes come out, you must run in the opposite direction.

Collect four Magatama Beads.
Collect four Tome Pages.
Successfully complete the game.
Defeat any Boss.

Put the Sprit Black Raven at the bottom of your Spirit Unity Menu. Then, put Bason in the L slot.