The warrior

The warrior is a Champion fighter: d10 hit die, a fighting style, and Second Wind (1d10 plus level, once per short rest). It has Action Surge from the first contract, gains its Champion critical-hit range (a crit on 19) by the second, and doesn’t reach Extra Attack until the hardest of the four fights. There are no 2024 weapon masteries here — an Attack action is one swing until Extra Attack makes it two.

The player controls the warrior directly. Its job is the “door”: whatever hexes stand between the party’s casters and the current threat. On the well that’s the lip a cluster wants to reach; on the brushline it’s the body a needler would rather shoot; in the hollow it’s the line that keeps a touch off the healer.

Second Wind isn’t a reflex to spend early. Hold it for the hit that would actually end the fight, since a single sitting gives no rest to earn it back.

What goes wrong

Chasing a cluster to finish it off, when holding a line that keeps the hit off the casters matters more than a tidy kill. Touring ahead of the party instead of holding ground. Treating trees and camp kit as empty hexes they aren’t. And expecting a mastery or bonus action this chassis simply doesn’t have yet — the rail won’t invent one.