Maou to Yuusha ga Jidaiokure ni Narimashita @comic

Igusa, a young guy obsessed with all things "evil," gets reincarnated as the very Demon Lord he's always admired—only to end up in a seriously rough situation. The new world he's reborn into has been wrecked by an interstellar war, leaving both swords and magic in decline! He finally becomes the Demon Lord, but the planet he was supposed to conquer? Yeah, it's already on the verge of collapse... That's when a girl calling herself a "Hero" and a beast-eared girl from another world show up. Without hesitation, Igusa forces them into his ranks, grinning like a true villain. No land left to conquer? No problem. He'll just take over the entire universe! Wielding cheat-level skills and magic, he commandeers a crashed warship and sets off into the vast reaches of space alongside his tamed(?) companions. All for the sake of his aesthetic of evil! So begins an otherworldly tale of shadows and schemes, where a man and the girls bound to him charge headlong and single-mindedly down the path of evil!

(Source: TO Books, translated)