She Devil: Karma Akabane x OC (Ass Class)

Imagine a live filled with screw-ups. Your mom was a drug addict who's currently doing her time in California's security prison for murder, and your father hung himself out of grief for his lost wife, leaving you a confused little girl wondering if he loved you at all. You knew your mom didn't; she sold you for a couple of quick cash-and to escape you and your father. Thus leaving you as an orphan, depending on a thief on the run to get you out of not just this state but the country.
So you're in Japan. You made it there. Congrats. Now what? You need money, and it's not like people just hand free jobs around to children, specifically street rats squatting in an old warehouse.
Of course before you find out, you're kidnapped. Don't worry, you escaped mostly unscathed, but it came at a horrific cost.
Despite how your partner in crime is making the dough rolling, you still need money. Then BAM! An opportunity. An opportunity to get enough money to buy an actual home. Enough money that you wouldn't need to work for the rest of your miserable lives.
Of course, though, there's a catch. You have to kill someone. Or rather, something, considering that your teacher has more tentacles that an octopus and a constant smile on his face that makes you wonder if he's planning your very demise.
Sounds easy enough, right?
Hahahahahah....no.
He moves at Mach 20, which is about 15225.95 miles per hour. Nearly impossible to touch alone, so impossible that not even the government can control him.
So, it must suck to be Melody Spires, right?
Of course there's at least a benefit-she found a love interest.
You tell me who it is.