The boy in the next bed, with the same disease and the same nickname as every boy before him, who grows up rich and does not want to be cured quietly.
Lucien arrives at a hospital in Greece as a ten-year-old with the same rare blood disease as Michael Morbius, who renames him Milo, the name he gives every boy who shares that bed. They grow up together, Milo wealthy and Michael brilliant, and Matt Smith plays the adult Milo in Morbius, with Joseph Esson as the boy. Smith was originally announced as a different comic character, Loxias Crown, before the part was rewritten into a mirror of Michael himself.
It is Milo’s money that puts Michael’s cure on a mercenary ship in international waters. When the cure works, and turns Michael into something that kills for blood, Michael refuses to give it to him.
Minor spoiler
He takes it anyway, kills a nurse with it and lets Michael take the blame, and when Michael understands, urges him to embrace what they are. He kills Emil Nicholas, the man who raised them both, and mortally wounds Martine. Michael restrains him with a swarm of bats and injects an antibody he had built to stop him, and Milo dies.