​This character is a tribute to the American thrash metal band from California with the similar name Slayer. To unlock Sleigher choose one of the new Christmas Characters (Shooty Feet, Elfabear, Blitzen, Ho-Ho-Hobot, Hoppy Holiday, Poley) and defeat every Christmas enemy occurring in one round including the Christmas Boss.
It may also be possible that you need to beat round about 3 christmas bosses in different rounds. If you tried it and unlocked Sleigher another way please leave us a comment.

If you know how to unlock the other new characters of the Christmas Holiday Update please comment on the bottom.

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