Akali, the Rogue Assassin

Commander ninjutsu {u}{b}({u}{b}, Return an
unblocked attacker you control to hand: Put this
card onto the battlefield from your hand or the
command zone tapped and attacking.)

Perfect Execution — Whenever a Ninja you control
deals combat damage to a player, reveal the top card
of your library and put that card into your hand.
Each opponent loses life equal to that card’s mana
value.