Akuto keeps insisting he doesn't want to be the Demon King while every force in the universe conspires to make him one anyway, and the show mines comedy gold from watching him fail to control literally anything around him. The ecchi bits aren't window dressing, they're part of the chaos, each girl a different flavor of "this is happening whether you like it or not." By the finale, you realize the show spent twelve episodes asking whether destiny is something you choose or something that chooses you, then answered it by having Akuto trip into his own prophecy anyway.
Akuto Sai enrolls at the Constant Magic Academy expecting a normal student life. Instead, a prophecy reveals he's destined to become the Demon King, a fate that horrifies him but somehow attracts every girl on campus. Suddenly he's juggling romantic advances from classmates, faculty, and an android designed specifically to seduce him, all while trying to convince everyone, including himself, that he has no interest in becoming evil. The real tension simmers beneath the comedy: Akuto desperately wants to prove the prophecy wrong, but his growing magical power and increasingly demonic circumstances keep pulling him toward the very destiny he's fighting. His attempts to stay good clash constantly with the chaos erupting around him, each magical incident bringing him closer to the role he refuses to accept. It's equal parts absurdist romance and action fantasy. The show swings wildly between slapstick harem shenanigans and genuine stakes about free will versus fate. If you want something that takes its premise seriously while never taking itself too seriously, this scratches both itches at once.