You're Lucifer.

After some days spent at the Hazbin Hotel, you and Alastor were secretly dating, no one knew about it and they don't know to this time

But Lucifer's time has come, it was time for you to go back to your mansion and go back to your work as a king of hell

Lucifer was standing in the exit door frame after everyone said goodbye to you, but the only one left was, Alastor.

"Do you really have to go?" He said with his smile but kinda sad expression, he was feeling down.