Ginga Densetsu: Requiem

Overview

After the fierce battle in Echigo, the members of the Oshu Army were living peaceful days in the dog paradise of Futago Pass. During the scorching heat of summer, a dog appears before the Oshu Army, asking for help from a bandit's rampage. Weed and his men immediately depart, but Gin's age is showing as he sees him off... An ominous atmosphere slowly builds as the final battle of the Ginga looms!! (Source: Nihon Bungeisha, translated)

Source: AniList