Fate/stay night, Akikan! Recommendations
The mood is completely different, but these anime both have the master/servant thing, a competition to reach an objective, magic, romance, super powers, and fights.
Also, both are harem and have a tsundere in them.
Believe me or not, I enjoyed Akikan! more than FSN.
Both animes are about receiving or meeting a partner (coincidence or not) to fight in a survival game, and aim to defeat the other partnerships to win the game.