Sultai Flayer
The threshold here is the whole design: not "a creature dies" but a creature you control with toughness four or greater. That clause turns an ordinary aristocrats trigger into a payoff that only fires for the fat side of the board, which is exactly where green builds its bodies anyway. The 3/4 stat line is no accident either: the Flayer clears its own bar, counting itself among the qualifying deaths and returning four life when it falls. Where most life-gain-on-death effects scale with raw creature count (the wider the better), this one rewards going tall: chunky midrange beaters, defensive walls, the kind of high-toughness blockers that survive a turn and then get traded or sacrificed for value. The four-life chunk is sized to matter on each individual death rather than dribbling out a point at a time, which makes it a real clock-resetter against aggression when you are losing big creatures in combat. It is a narrow engine by construction; the toughness gate pays for the four-life burst, and it wants a board of substantial creatures rather than a swarm of expendable ones. That specificity is what keeps it interesting: a drain-the-life-back card built for the slow, grindy green-base decks rather than the fast sacrifice shells most death-payoffs call home.

