Arika, the Dragon's Shadow

Partner, Commander Ninjutsu {r}{r} ({r}{r},
Return an unblocked attacker you control to
hand: Put this card onto the battlefield from your
hand or the command zone tapped and attacking.)
Whenever Arika deals combat damage to a player
exile the top card of that players library, you may
cast that card until the end of your next turn, if
you don't put that card into it's owners graveyard,
that player loses life equal to that cards converted
manacost.