Toaru Kagaku no Accelerator S01

The ranking of the citizens of Academy City is a 6-tier system, from Level 0, which has no power, to Level 5, which has a great deal of power. Out of the millions of residents of Academy City, only 7 of them have reached Level 5, and the one who holds the highest rank among them is called the Accelerator. After protecting the last one at the cost of all his power, the Accelerator focuses on the strongest at Level 5. After recovering in the hospital, the Accelerator is living a quiet life until he saves the life of Estelle Rosenthal, a mysterious girl who has a photo of the last one with her. Unfortunately, the Accelerator finds himself involved in a battle with a sinister organization called the Disciplinary Action, which is trying to employ the last one for a perilous mission. Now that their plan is in motion and they are pursuing the young girl, it is up to the strongest citizen in the world and his new companions to protect the last one and defend Academy City.