Dokuchi Shadow-Walker

The tension in every ninjutsu design is what the creature does when it swaps in and how much you paid for the trick. Here the answer is nothing but stats: a 5/5 with no combat trigger, no evasion, no ability beyond the ninjutsu clause itself. That reads like a whiff until you count the mana. Ninjutsu for puts a five-power body onto the battlefield tapped and attacking, unblocked, for four mana total, which is a rate a hard-cast six-drop cannot touch. The design leans on the mechanic's built-in ambush: you return an already-unblocked attacker to hand and this arrives in its place after blocks are declared, so the five damage connects with no chance for the opponent to trade for it. What balances the raw efficiency is that the ninjutsu path demands a working attack step and a creature that has already slipped through, so the card is dead weight in a stalled board and useless the turn it lands unless the plan came together on the swing. It is the vanilla end of the ninjutsu spectrum, the beater you reach for when the cheaper Ninja bodies want backup and the deck needs a big unblocked hit rather than another triggered-ability engine. The hard-cast line at exists mostly as a floor; the card is built to be cheated in from an unblocked attacker, and everything about the rate assumes you will.