I'd considered making one of them a veteran lich who has conquered other versions of himself and the other a 'naive victim' lich but that was too on the nose for what Marvel had been planning to do with Kang and also narratively unnecessary.

In mine they are yuan-ti abomination liches, and since they are each other's phylactery, their bodies were intricately crafted to be serpentine ebony or ivory. Similar to yours in some ways.

Thanks for the stories, sounds like it was fun!