Inshoku Ou Demar

Rosalia is a beautiful adventurer who once hunted demons alongside heroes. After retiring from the front lines, she ran an orphanage in a remote area, living a quiet life while taking in orphaned children. But one day, she found an insect in the orphanage... It was a split body of Demar, the King of Lust, a powerful enemy she had defeated during her time as an adventurer. "You can't be... you're still looking for me..." Rosalia stood alone, trying to ward off the demonic clutches of revenge, but countless tentacles attacked her ripe body――!?

(Source: PinkPineapple, translated)