And I see there being a bit of past with Harlow and Azrael, and it's one of the few reasons Lucifer isn't worried about Harlow corrupting.

And poor Zach would be right next to Billie as she starts losing her mind. 

Aw... Arch Mage feels loved now..

Presumably. Or perhaps certain mages are granted longevity for purposes like being the Arch Mage