Rem Galleu is one of the main characters in the anime series 'Isekai Maou to Shoukan Shoujo no Dorei Majutsu' (How Not to Summon a Demon Lord). She is a Pantherian, a race known for their cat-like features, and possesses sharp instincts and agility. Rem is a skilled adventurer and a summoner who initially attempts to summon a demon lord to assist her in her quest. She becomes one of Diablo's companions after failing to control his summoning, leading to their adventures together. Rem is characterized by her calm demeanor, intelligence, and determination to achieve her goals.