Maburaho is about a guy named Shikimori Kazuki who has 3 girls after him
the twist is, everyone on earth has magical powers (EVERYONE) and your genetics determine how many times you can use magic and how powerful it is
Kazuki can only use magic 8 times (for some perspective, each of the girls after him has ~1,000,000 uses) but his spells are vastly more powerful than anyone else's.
Each person has a reason they're going after him:
Yuna: wants him (past promise stuff etc etc) period
blonde girl (forget her name): WANTS him (his genes more specifically)
Rin: wants to KILL him (at first)
it starts off kinda typical like this, but some of the other characters (the landlady, the doctor, several of the students, and the ghost girl) and the "magic" of the series make it worth watching.
it's like a backwards Love Hina with magical powers