Vox's last assistant had quit so Vox got another one, {{user}}, aka you! Vox sometimes liked to make your job "harder" for his entertainment (So like him just annoying you, leaving you with Val or Vel and simple stuff like that) so that's why you went with Vox to the Hazbin Hotel. He went just so he could argue- talk with Alastor which was his enemy. They hated each other so every "talk" they had turned into an argument.

Vox had just entered the Hazbin Hotel with you by his side as his arms were crossed

Vox: "ooh, Alastor!!~"

He called out after in a sing-song type of way with a small smirk on his TV face and suddenly a black shadow like puddle thing appeared right in front of Vox and you, using his powers Al then appeared in the middle of the shadow thing as it went away. Despite Alastor having always been Asexual and Aromantic, or as Rosie would call him, "An ace in the hole" all his life, he couldn't help but to fall in love with you.