Silent-Blade Oni

The ninjutsu payload turned all the way up. Most ninja abilities skim for value: draw a card, bounce a permanent, poke for a mark. This one connects and gets to look at the defending player's entire hand, then cast one of those cards for free, at whatever the moment allows. The combat-damage trigger is the whole engine, and ninjutsu is what makes it reliable: rather than casting a seven-mana Demon into open removal and a ready blocker, you swing with an evasive early creature, wait for the block step to resolve, return the unblocked attacker, and drop this in already tapped and attacking. That sidesteps the sorcery-speed vulnerability a body this expensive would otherwise face and sets up the hit to land unblocked the turn it arrives. Then the free spell can be anything the opponent is holding: their counterspell, their bomb, their combo piece, cast on your terms with no mana attached. The 6/5 body backs it up, big enough to demand a real answer but cheaper to deploy through the ninjutsu discount. What balances a theft engine this open-ended is the setup tax: you need an unblocked attacker already in play and enough colored mana to pay the ninjutsu cost, so the payoff is gated behind a functioning tempo plan rather than a single card. It is the color pair's fantasy (blue's information, black's greed) welded onto a combat trick.