WALLMAN

After being betrayed by his country, Jirou left his past as a hitman behind and came back to Japan were nothing mattered anymore in his eyes. But that's before he mets Nami, an active hitman seeking vengeance for her father's death. But not any hitman, a wallman! Jirou is then brought back into this world and teams up with her. — Description from AniList community (anilist.co).