Marceline's mother was a human...
Was Marshall's father also a human too?
Did he know your father?
I wonder how the demons of the Nightosphere saw him...
I've seen a headcanon where Marshall lived with both his father and mother, and he was frowned upon in both worlds.
He had both parents,, , but at what cost lmfao 😭 love the headcanon
For my AU/headcanon, i'm still keeping the human/demon parents for Marshall, but of course, with some differences. He spent most of his childhood and teenage years with his mom, but he still saw his dad a couple times as a baby when they visited Ooo. He doesn't remember much about him as an adult, though.
They gradually stopped visiting Ooo as Marshall Lee grew older and became more excited to command the Nightosphere, just like his mom. She played a huge part in separating him from Ooo, and consequently, his father, so that he'd focus on leading her evil forces and whatnot.
I don't think the demons would know that he's half-human because I highly doubt his mom would give such details to them, of all people. The demons just saw him as their next commander, so there's not much to say about them ¯\_(ツ)_/¯
His dad is dead in this too.