Elf Tensei Kara no Cheat Kenkokuki

A skilled magician, seeking to avoid dying of old age, discovers a method to reincarnate using magic he developed. This process repeats many times, and during his 31st life, he is reborn as Syril, a boy living in an elven village. The village is under human rule, and the elves are treated as animals. At age 14, Syril regains his previous memories and decides to assist his childhood friend, a girl. The narrative follows the development of a new nation starting from that village, aiming to be a place where all races can live together.