Rith, Liberated Primeval

Excess damage is the mechanic that finally gives combat a reason to reward overkill, and this legend builds its entire engine on it. The end-step trigger asks a precise question: did any creature or planeswalker an opponent controlled soak more damage than it could hold this turn? A blocker ganged up on by two attackers, a burn spell that overshoots a small body, a big creature swinging into something far smaller: each clears the bar, and every end step that answers yes prints a 4/4 flying Dragon. Note that the 5/5 has flying but not trample, and that is the point. Trample works against this design: it assigns only lethal to the blocker and pushes the rest to the player, so a trampler deals exactly enough unless you deliberately overassign. Excess damage rewards the opposite instinct: pile more onto a target than it can take, and bank the surplus. That rewires the usual combat math, where players stop calculating once lethal is assured; here the waste becomes the payoff.

The ward on this Dragon, and the ward it hands to your other Dragons, is the protective floor that lets the engine survive a turn cycle to fire again, since the token only lands if the body sticks around to reach your end step. Rith is a returning name (an earlier incarnation flooded the board off a single connection), and this incarnation keeps the token-swarm throughline while trading the attack requirement for a cleaner, more punishing condition: you no longer need to hit a player, only to hit something harder than it could survive.