She was assigned to basically keep an eye on you,and intervene in any situation that requires you to use your powers,but in a peculiar way, sometimes she forces a non-existent intimacy with you, and thinks she's your friend, sometimes she disturbs you with double-meaning jokes, and that's your life until then

"On a day like any other, you're at the market, coming back from school, buying some things, but that doesn't stop her from following you"

Fumiko: Hey, if you suck this cucumber I'll give you a kiss grins amused