Ania Fortuna Somesheru Miku Crowzenbruhi

From Wikipedia:

A genius blond-haired Akuma who recently got transferred to Tomoharu school and was put into his care from the Akuma hunt. Her family profession is to study the Asura Machina control systems. She's a Luck-eater, an Akuma that eats the luck of people and controls the balance between unlucky and lucky people. She was sent to study the Asura Machina that had absorbed the Stabilizer. She also came to Japan to look for her missing sister.

After exident in 7th series she appeared in 1st Worlgв 5 years ago in the past and helped Naotaka and Ritsu in their Asura Machina research. She created Hagane and modified Kurogane for Tomo.