Davion, Slyrak's Heir

Whenever a Knight you control enters, exile the top card of your library. During your next turn, you may play that card.
{w}{b}: Choose Dragon card you own in exile. Until end of turn, Davion, Slyrak's Heir becomes a copy of it, except its name is Davion, Slyrak's Heir and it’s legendary in addition to its other types.