Dekisokonai to Yobareta Motoeiyuu wa Jikka kara Tsuihou sareta node Sukikatte ni Ikiru Koto ni Shita

A boy named Allen was unable to receive the gift of God's bounty, and called a failure. But his true identity was a former hero with memories and powers of his previous life!? Fortunate to have been expelled from his duke's family, Allen was trying to start a free-spirited journey, but he encountered an assassination attempt by a former fiancée...!? An unwanted heroic saga begins for the former hero who wants to relax in this world!

(Source: TO Books, translated)