Back when my powers first woke up and Shura took me on as a student, she put that ring on me. When someone says the activation words, it causes pain and forces me to stop whatever I'm doing. And because of it's magic, I can't remove it. Only the person who put it on me can.

[Despite how awful that sounds, he smiles.]

I've always had trouble controlling my power. I lost control of myself and became a monster way too many times, back at the beginning. I kept thinking 'it's okay, I'm using my power to help people, so it's fine.' But it wasn't fine, because I would lose control and then start hurting innocent people too. So this was the church's solution, to keep me in check and to protect the people around me.

[Even if he hadn't lost control like that in ages, not before the incident here with Tsuru. If someone had known the words to activate the ring, then maybe...

...no, Rin can't think like that. 'What ifs' are pointless, there's no changing the past. He has to own up to what he did and carry on.]

It might not be exactly the same for you, but that's kinda what whatever's under the bandages are for, yeah? "You fucked up, we're putting this on you so you don't fuck up again" or something like that.