Shen-Ji, Invisible Blade

Ninjutsu {u/b}{u/b} (Return an unblocked attacker you control to your hand: Put this card into play tapped and attacking.)
Whenever Shen-Ji attacks and isn't blocked, he gets +X/+0 were X is the number of blocking creatures defending player controls.
{t}, Sacrifice a Ninja: Return target creature to its owners hand. That creatures owner gains 1 life.