R18: Isekai Villain

Ren was summoned to another world as the Hero, blessed with an unprecedented SSS-grade magical talent. But becoming stronger requires mana—and Ren discovers a very unusual way to accelerate his growth. Princess Lyra, innocent and sheltered from the world, soon becomes his daily companion. What begins as a secret arrangement quickly turns into something far more intimate. While the kingdom expects its Hero to prepare for the Demon King, Ren is busy growing stronger in his own way—with a beautiful princess at his side.