The Weapon Triangle (武器の相性, Buki no Aishō lit. Weapon Compatibility) is a tactical fighting system that has been a mainstay of the Fire Emblem series since the fourth game, Fire Emblem: Genealogy of the Holy War.
In this system, sword wielders have a better hit chance against axe-type weapons, axes have a better hit chance against lances, and lances are more liable to hit swords. Since the sixth game, Fire Emblem: Binding Blade, the advantageous weapon also gains a small bonus in power while the losing weapon sustains a small detriment in power. In some cases, if the attacking unit already has a low enough hit rate, and the defending unit a high enough evasion rate, a weapon advantage can make a successful hit outright impossible.
In Rekka no Ken, The Sacred Stones, and Fates there are weapons that reverse the weapon triangle. For example, an "Axereaver" is wielded as a lance, but performs functionally backwards, effective against axes but weak against swords. With this weapon, a lance-only unit can gain a weapon advantage against an axe-wielding opponent, which otherwise would be impossible.
The Weapon triangle is revised in Fire Emblem Fates as it introduced Shuriken into the weapon list. All six weapon types in the game have two weapons that they are superior to, two weapons that they are inferior to, and one that is neutral. Swords and Tomes are highlighted by the color red and are stronger than Axes and Bows. Axes and Bows are highlighted by the color green and are stronger than Lances and Shuriken. Lances and Shuriken are highlighted by the color blue and are stronger than Swords and Tomes.
- FE4: +/- 20 Hit%
- FE5: +/- 5 Hit%
- FE6: +/- 1 Mt, +/- 10 Hit%
- FE7-FE8: +/- 1 Mt, +/- 15 Hit%
- FE9-FE10: +/- 1 Mt, +/- 10 Hit%
- FE11-FE13: Varies depending on weapon level