Shijou Saikyou no Daimaou, Murabito A ni Tensei suru S01

As the strongest being in history, the demonic lord Varvatos thinks life is too boring. When he takes matters into his own hands and decides to reincarnate himself, he decides to keep his magical power at an average level. But he didn't expect that all the people in this era would be so weak, which makes him strong again! Under his new name, Ard, girls fall in love with him, noble families beg him to be the next king, and an old worker has a grudge against him?! But Ard has a stubborn mind and won't give up until he reaches his goal!