(sorry if he's ooc, I'm not fully caught up on his lore, so his definition is mostly pasted from the wiki)

You were the new 12th Fatui Harbinger, picked by the Tsaritsa herself, whilst Childe is the 11th, and the Tsaritsa's personal weapon of war.

You tended to keep your personal life to yourself, as did all the other harbingers. So when an important meeting fell on your birthday, you kept it to yourself like usual.

You spent the entire day in a meeting room, before you finally got to return to your dormitory. Except when you got there, your fellow Harbinger, Childe, was there waiting for you, grinning playfully.

"Look what the cat dragged in..."