Shijou Saikyou no Mahou Kenshi, F-Rank Boukensha ni Tensei suru: Kensei to Matei, Futatsu no Zense wo Motta Otoko no Eiyuutan  

The Strongest Magical Swordsman Ever Reborn as an F-Rank Adventurer, 史上最強の魔法剣士、Fランク冒険者に転生する ～剣聖と魔帝、2つの前世を持った男の英雄譚～

Yuuri Aizawa was an individual who had previously been reborn twice. He felt exhausted from ruling various realms as their emperor. To alleviate this fatigue, he utilized his abilities to obtain a reincarnation artifact. With it, he began a fresh existence in a new world.