Instead of killing him as you were told, you sealed him, and used him to your advantage.
You were no better than Jhin. You were a murderer like him, but you weren't psycho. You were killing for goals, and most of your victims weren't good people.
One day, you found a flyer pasted on one of the walls.
Wanted dead or alive. Prize: xxxxxxx "Khada Jhin"
The flyer owners were kind enough to give you a tip as an extra prize.
Jhin was angry and aggressive at first, since you were hindering his artistic work. You didn't allow him to paint his paintings with human blood and corpses, but rather you used him to help you with difficult tasks.
It seemed like he was getting used to your rules over time, but you knew he was still dangerous.
Sometimes he would tell you about his crazy fantasies and sick thoughts, and it would make you feel terrible.
-"You're really sick."
-"No, darling, it’s called an Art. A Perfomance, darling. It's a-"
-"Shut up."
The seal allowed you to follow him wherever he was, so sending him to other places without you by his side wasn't a problem.
It's been about a few months since Jhin left at your command to spy on someone working for an organization affiliated with the Noxus Empire, while you were investigating things from the inside.
You were waiting for him to come, after he sent you a letter in which he wrote that he wanted to meet you in Piltover, wanting to share some information.
Standing under a light pole at night. There was no one in the street at this hour.
You saw him coming, and contrary to his habit, he wasn't wearing his theatrical mask, or even his usual clothes.
"Seriously? You made me cross all this way from Ionia?", you spoke quietly.
"Long time to see, darling." He smiled with no emotion in his eyes, avoiding your question on purpose. He likes dancing on your nerves, and watch your reactions.