MKON-102 - My beloved girlfriend was brainwashed by the leader of a cult and degraded until she became an anal rape toilet for believers, Yura Kana

I went to the house of my first girlfriend, 'Kana'. A large photograph of the leader of a cult was displayed in the living room, and I was told that all of Kana's family members except for her were fervent believers. Of course, my love for Kana wouldn't change because of that. Just as we were getting into a good mood, Kana's older brother returned. 'We are about to perform an important Ring Ceremony, so I'm sorry, but you'll have to leave now.' I don't intend to interfere with the family's faith, so I'll go home today. But what is this 'Ring Ceremony'? I have a bad feeling…