Marx

Marx Nova is the in-universe incarnation of Satan. Contrary to many others, he mostly dwells on Earth, leaving Hell with whatever. He was a key member of the Sacred Union before being exiled for allegedly betraying the group. However, his secret return and conversation with Union Leader Pidermin would have a long lasting effect on the rest of the story and the fate of the Council.

History
Marx was born in the depths of Hell itself, the direct spawn of Archdemon Masahiro Sakurai. However, he never really got along with his father. Their ideals would often clash and directly oppose each other, and Sakurai was too busy with personal projects to ever tend to or raise his son. To remedy this, Marx would cross into the world of the living. To Planet Popstar, a nearby planet to Earth. He would attempt to take it over for himself, but was swiftly stopped by Kirb.

Marx returned to Hell after his defeat, where he was taken under the wing of the Satan of the time. Big boy Lucifer himself. Several years passed since then, and Lucifer would pass on his iconic ability to “Deal” and his title of Satan to Marx in exchange for his capacity to go to Heaven. As Marx doubted he could ever ascend to Heaven anyway, he accepted, but soon realized Lucifer was already gold hearted enough to ascend and left him there, alone.

In the current era, Marx is a planeswalker, usually staying on Earth to strike “Deals” with whoever he so chooses. During his stay, he earned quite the reputation for himself. One day, a missionary from the Land of Pink and Grey tasked him to create the manifestation of one’s own Corruption in exchange for his own soul. He wanted it for research, it seems, to stop the Corruption from spreading. But he didn’t quite understand what kind of damage losing one’s soul would give. Hence his new pseudonym; Lost.

After the creation was complete, the force-corrupted test subject seemed to have his entire memory wiped away. As if he was born from nothing at all. They set him back where Lost had taken him from; Rural Canada. However, Marx would have to face him once again someday, when he and his group would confront and beat the shit outta him for creating Guilty Conscious. He’d later join their Union, who’d later merge into the Brady Council.

Influence on BB4
Back when the Union was stranded on an island on their pursuit of Guilty Conscious, Tabuu approached Marx and told him of a foresight he’d seen. He told him Pidermin would die very soon if he were to remain in the current time, so he offered his own life so that Pider could skip past the attack from Faye and bypass the events of BB3.

Furthermore, he‘s the one who created Thibault and Élaine from Pidermin’s genes, raising them afterwards. He was also the reason why Aussie had ended up in their world, after making a few deals he shouldn’t have in her’s. And god knows how much more he did-