War ptsd

ML was a child soldier and later mercenary

FL was a child soldier

ML was a soldier and his lover died to protect him

ML was a soldier and his unrequited love died in front of him, but he also has ptsd from war in general

Violet Evergarden (novel)

FL was a child soldier and her superior (her first love) died in front of her (everybody probably knows already but: he's the ML and he's not dead)

(ML)