Cruel Sadist

A repeatable creature-kill engine that grows itself and then spends that growth, all packed onto a one-mana body. The math is deliberately punishing: every counter costs a tap, a black mana, and a life point, and the damage activation costs three more mana and ties up the tap again, so the assassin can charge or fire but never both in a single turn. That sequencing tax is the whole balance: a control player has to commit several turns of mana and life to stockpile counters before a single big shot ever lands, and an opponent who sees the storage growing has every chance to kill the 1/1 in response. Removing the counters shrinks Cruel Sadist back toward dead, so each use trades its own survivability for a kill. The design lineage is the slow-build pinger, the Royal Assassin idea reworked so the ammunition is a resource you meter out over time rather than a tap-to-destroy you fire at will: more flexible because it scales to whatever toughness you have banked, less reliable because the body holding that ammunition is the most fragile thing on the board. It rewards a grindy, mana-flush game and asks nothing of you in a fast one, which is exactly the tension a one-drop assassin with this kind of activation cost is built to carry.