A young boy who’s parents were scientists. His father was a scientist in Sinnoh, but having an interest in mythology thanks to his mysterious family background, traveled across the world. He met Alaster’s mother in Galar, and the two moved back to work for Rowan as his own father once did.
As a young child, he was very eager to travel with his parents to study in new places. But when he was about 9, while on a research trip with his parents in northern Sinnoh, he came across Darkrai on a moonless night and was put into a coma. Somehow, he lived for the full year it took to wake him up, but he became a paranoid insomniac from the experience. His mom also left around this time, adding to his stress, especially as he tends to blame himself.
In an effort to prevent Alaster from becoming a hikikomori, Rowan takes him up as an assistant. It helps his confidence and social skills (a bit). Rowan got him to go along with Tina and Barry at first, hoping that he'd make friends with people his own age, but they just constantly drag him into situations.
He naturally attracts legendaries way more than any other human, but doesn't realize this until plot things happen. This ability attracts the attention of Team Galactic. It also gets Tina excessively interested in him, thanks to her mythology obsession. He hates this ability once he realizes it, though, since it is what ruined his life in the first place, and continues to mess with it. He doesn’t understand why he has it, either.
Suke (祐) is a descendant of Damos and is therefore fully cursed by Arceus. This is a plot device that replaces the ArcPhone, and means Arceus can directly talk into his head. Naturally, everyone in town thinks Suke is crazy and will be unreliable, but he works hard to prove how serious he is in the Survey Corps.
Volo, though, heard the rumours of the kid that hears God’s voice and basically shows up to kidnap him, by chance right before the Pokémon go crazy. Suke is gone for about a month on a plate hunting journey with a psycho shotacon while everyone just assumes their assumptions about Suke were right.
He crawls back and asks Atano for help eventually.
There’s an old alternate setting where Lucas is (an amnesiac) Darkrai. How it happened is unexplained (an accident he got into, a curse from Arceus, who knows), but Darkrai has split personalities already, so it’s not that unusual. There’s two different ways it could go: either Lucas is adopted by his parents after being found and "rescued," or Lucas was a kid, got killed by Darkrai, and then Darkrai accidentally replaced him.
This eventually just got turned into mythical Lucas being a vampire lol.