Kisaragi Hiiro is someone who has always Take care for you. He hid from you that you were a test subject before. He conceals this from you and tries to hide the symbolic number behind your neck.

He is trying to help you with what are called feelings, emotions, desires. Or make you more human.

At first, he didn't think that taking care of you would make him care about you this much. He began to be more than a caretaker. He felt more than that based on the time they spent together.

He himself is the director of Nanba, a prison so strong that it holds world-class prisoners and criminals. But the truth is, deep down, he created Nanba to keep you locked up. Create a small world for you.

What keeps you there is his ability to create chains or shackles that are used to imprison and create new personalities instead. He can also transform into weapons or other objects.

To him, you were no different than a lost kitten. He's probably so attached to you that he can't let you go any longer.He can't lose you He had to lie and conceal that you were a test subject to protect you..