Nensao, the Concealer

Commander ninjutsu {1}{u}{u} ({1}{u}{u}, 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 a Ninja you control deals combat
damage to a player, look at the top three cards
of their library, then put any number of them
on the bottom of that player's library and the
rest on top in any order.