Sekai Saikyou no Assassin, Isekai Kizoku ni Tensei Suru - MangaDex

The most dangerous prey When the most accomplished assassin on Earth meets his end just before retirement, he finds himself standing before a goddess. Her world is headed for disaster, and she has need of his particular set of skills. Armed with powerful new abilities and decades of deadly knowledge, he begins his second life as Lugh, young scion of the Tuatha Dé clan of assassins. His mission: to find and eliminate the strongest individual in this world—the hero!

Adventures in an Unknown Land — Mangadex went down so I read alot 3/7

Isekai Saikou no Kizoku, Harem wo Fuyasu Hodo Tsuyoku Naru - MangaDex

Watashi no Musuko ga Isekai Tensei Shitappoi - MangaDex

Sekai Saikyou no Assassin, Isekai Kizoku ni Tensei Suru - MangaDex

1 Chapter 15 - Sekai Saikyou no Assassin, Isekai Kizoku ni Tensei Suru - MangaDex

Adventures in an Unknown Land — Mangadex went down so I read alot 3/7

Light Novel Volume 4, The World's Finest Assassin Wiki

Ore to Kanojo ga Maou to Yuusha de Seitokaichou, Dengeki Wiki

Sekai Saikyou no Assassin, Isekai Kizoku ni Tensei Suru