The Weapon Triangle and Durability

With advantage, a unit gains accuracy against its prey and loses it against its predator; in some games the swing extends to damage. The design purpose is legibility: a glance at an enemy's weapon tells you who should fight them, turning an army of stats into a set of matchups the player can plan around. The Fire Emblem Wiki's weapon triangle article records that the system remained mostly unchanged until Fates, an unusual two-decade stability for a series that reinvents itself constantly.

Three Houses largely let the triangle lapse, surviving mainly as the Breaker skills that counter one weapon type. Engage (2023) brought advantage back with a new job: instead of bending accuracy, advantage on the attack now breaks the enemy, leaving them unable to counterattack. The thirty-year-old triangle survives by changing what it pays out.

Weapons wearing out is older than the triangle: it is in the 1990 original, and it is the quiet engine of the series' economy, turning inventories into budgets. Genealogy softened it with repair shops, letting prized and legendary weapons be restored rather than replaced, which suited a game about inherited arms. Fates abolished breaking outright, replacing it with trade-offs: stronger weapons now tax their wielder's stats instead of their lifespan. Three Houses restored durability and bound it to Combat Arts, and Engage settled between the poles, with most weapons unbreakable and staves still limited. The argument between the two designs, scarcity against freedom, is one the series is still having with itself.