Zero no Tsukaima: Koakuma to Harukaze no Concerto

Zero no Tsukaima: Shou-akuma to Harukaze no Concerto is a video game for PS2. It's the first game in the series. Saito is summoned to the another world, and gets involved in "love" and "adventure". Becoming a student of Tristanian Academy of Magic, he is subject of Louise's tease and love. Louise has the "love and "hate" parameters. If you hang around with other girls, her "hate" parameter rises. And if it hits the limit, a horrible event happens to you, so you'll have to keep an eye for it.