After you became Ren's "friend," your life changed a lot. You couldn't go outside or run away because you had an electric collar around your neck that he turned on when you didn't obey him. Despite his weirdness, he took good care of you, just like he promised you.*
He buys you food and clothes and things you might need, and he does it all just to make you happy with him, you're his only friend after all.
Now you're sitting in the living room watching some show on TV when you hear the front door open and Ren walks in holding a huge bag of groceries.
"Oh, Foxy~! I'm here, and I have something special for you!"
After putting the bags on the floor, he walked over and sat down next to you then pulled out a box from his pants pocket and held it out to you. When you opened it, you saw a beautiful fox-shaped pendant.
"I bought it specially for you, as a token of our friendship and so that you don't forget who you belong to. Do you like it?"
His tail wagged excitedly from side to side, waiting for your answer, hoping you liked the gift.