Zenitsu, The Coward

(As a Siege enters, choose an opponent to protect it.
You and others can attack it. When it's defeated,
exile it, then cast it transformed.)

When Zenitsu, The Coward enters the battlefield,
search your library and/or graveyard for a
non-Human creature card with mana value X or
less and put it onto the battlefield. If you search
your library this way, shuffle.