Karrthus, Tyrant of Jund
The entry trigger is the loud part, and it cuts two ways most theft effects do not. Gaining control of all Dragons, then untapping them, is a board-state coup tuned for exactly one kind of game: the showdown of big-creature decks where Dragons are the win condition and an opponent has parked a fattie that is now yours, swinging immediately because the static ability hands every Dragon you control haste. That untap-then-shared-haste package is what turns the steal from a swing in card advantage into an alpha strike with the very creatures your opponent spent mana to deploy: the stolen Dragons are not just yours, they are untapped, free of summoning sickness, and already pointed back across the table. The catch is a symmetry of a different sort. The trigger is conditional on Dragons being on the battlefield, so against a board with none it does nothing but resolve a 7/7 flier with haste, a fine if unremarkable rate for the cost. As a tribal payoff this is built for the mirror: its ceiling is highest precisely when opponents are also playing Dragons, and its theft clause punishes any field that converges on the same tribe. The shared-haste static ability is the quieter half, doing reliable work for your own Dragons long after the one-time enter trigger has resolved.
