Bria, Riptide Rogue

Prowess as a keyword lives on a single creature: it grows the body that carries it, one noncreature spell at a time, and then goes home at end of turn. The interesting move here is granting that keyword outward. Every creature you control becomes a prowess trigger, so a single instant is no longer a +1/+1 on one attacker but a board-wide pump, and the anthem stacks with a creature's own printed prowess (each instance triggers separately). That reshapes what a spell-heavy deck is actually doing when it casts a cantrip mid-combat: it is no longer sculpting a hand or protecting a threat, it is a combat trick that hits the whole team.

The evasion rider is the piece that turns the pump into damage. Each noncreature spell also makes a creature unblockable, so the anthem's arithmetic does not get walled by a single blocker: the spell that grows the board also picks the hole to run a threat through. The tension the design resolves is the old problem of go-wide spell decks, which build a battlefield full of small bodies and then watch them bounce off ground stalls. Here the same spells that add power also guarantee a lane for it. The 3/3 body is modest by four-mana standards, but the card was never meant to win by attacking alone; it wants a hand full of cheap noncreature spells and a board that turns each one into a lethal step forward.