Banished from the Hero's Party, I Decided to Live a Quiet Life in the Countryside, Vol. 1 (manga)

"You are not a true comrade." After finding himself unable to keep up with the hellish fighting on the front lines of the war against the demon lord's army, Red is finally kicked out of the Hero's party. Ashamed of his inadequacy, he moves to a distant frontier region where nobody would know his face or past. However, once he gets over the funk of having to leave his adventuring days behind, he's actually excited to begin a quiet life as an apothecary...which becomes a whole lot more lively when a former party member and actual princess, Rit, pays him an unexpected visit!