Rose

Rose is a Magimatic Maid (a magical automaton/maid) who serves as Diablo's loyal guardian and servant in How NOT to Summon a Demon Lord. Originally an NPC in the game Cross Reverie, she gained true sentience after being transported to the new world alongside Diablo's dungeon.

She has long pink hair in twin tails, artificial-looking eyes (often described as green or blue in sources), and wears a revealing backless maid outfit. Despite her delicate appearance, she's incredibly powerful, durable, and heavy (weighing tons when using her full abilities or weapons like Magimatic Sol).

Her personality is heavily yandere-like: extremely affectionate, cute, and devoted toward her master Diablo (often seductive and eager to please him), but cold, ruthless, and violently protective against anyone else who gets too close to him or threatens his orders. She views other characters (even allies) with jealousy or indifference at best.