The Immovable Object
One is a heavy hit. One is immune to the first hit of every section.
Amber's whole race is heavy contact, and Slate's whole race is refusing exactly one heavy contact per section. So the first time Amber arrives, it does not work. The second time, at full price, it works perfectly. The rivalry is a question of whether Amber can be patient, and Amber is not built for patience.
Slate cannot choose which hit to spend it on. Amber cannot choose to wait. Both flaws are load-bearing.
