I Will Exile You Again and Again ~The Guiding Book, the Book of Hope~

Elius, a young man who vows revenge against the Demon King for killing his father, encounters a mysterious man named Kuro who offers to shorten the required ten years of preparation for the Demon King's defeat to five. In exchange, Elius receives the skill "Guidance," allowing him to relive his life from age fifteen to twenty, discovering the necessary causes for defeating the Demon King. Through repeated cycles, he meets powerful individuals and feels confident in his quest. However, "Guidance" reveals that he must repeatedly exile Elein, a party member with the seemingly useless "Accounting" skill, who awakens as the "Ruler of Numbers" after each exile. While Elein grows stronger, Elius is scorned as incompetent. Despite the guilt and responsibility, he continues to exile her, believing she will eventually defeat the Demon King. This is the complete edition, including additional episodes and a new ending.