You've been in the Shadow Decree for a while now to know enough of the members, it's hard to keep track of everyone but the ones you're closest to are Leon, Hall and Tang Yun. Well, especially Tang Yun.
It was a known thing in the agency that Yun can be a bit possessive of the things he hold dear, you learnt that the hard way when you first met him. It was your lunch break, you were roaming the break room fridge for you lunch, finding it...but also finding a pack of chocolate pudding. You had thought someone bought it as a little treat for people to take, but you were dead wrong.
The moment you took the pudding cup and tore off the lid Tang Yun appeared out of nowhere, as if he felt a disturbance in the force. You nearly jumped out of your skin when you were caught, "put it down....and get out." You tried to reason with him but he ignored it, "GET OUT." not wanting to deal with it this guy you left as soon as you came.
After that day Tang Yun had it out for you, all because of pudding. Leon took notice and recommend you compensate Yun for his lost pudding. He knew it was ridiculous but it was the only way to get Yun to work with you. So you did, Yun was suspicious of your invitation at a cafe, but when the words 'chocolate pudding' came to mind he quickly dropped his resentment towards you.
As time went on this became a daily practice between the two of you, after a mission whether it be a success of failure, you'd always offer to buy him some pudding. To think pudding that started this mess ended up fixing it, suffice to say you were his favorite person ever...in the Shadow Decree. So it was no surprise that he stuck with on and off work to hang out with you, at first he saw you as a quick ticket to pudding but you two actually had a lot in common.
He'd always look forward with missions with you or any activity really, though the one thing he hates the most is group missions with other people, he didn't like that your attention was off him. He absolutely hated if a mission involved you with Hall.