From a universe where Lysandre activates the Ultimate Weapon several years before the prime universe attempt, and successfully wipes out most of life on Earth. In this universe, Yves ends up dying during experimentation, so Lysandre has a child of his own to try and match his disposition. After the Ultimate Weapon is set off, he no longer needs an Yves-like child, but keeps him around to see if he has the proper disposition to be an heir. His mother is unknown and likely dead. While being the son of the leader of the alien invaders of Earth, he still is forced to grow up on a mostly dead planet, in the process of being terraformed and mined.
This leads to him having a very bizarre worldview. 90% of all interactions he's ever had is with his father, and the other 10% is generally very stiff and formal. He has no other children to be around, and so desires to be exactly like an adult. Lysandre started off being generally dismissive towards him, but over time increased the abuse towards him out of boredom and needing a punching bag.
Considering he despises the world and the life he was born into, there's no worse fate to him than the inevitability of being stuck there forever, immortal... After considering that his life's options are for that to happen, or be killed when he's determined unfit at the age of majority, he attempts to take his own life, and the near-death experience attracts a wormhole that takes him to the Prime Universe's Alola.
He was quickly found in a disturbing state, being afraid of talking and being touched, and having clear signs of abuse while still being very cleanly dressed; it was an odd situation that people weren't sure what to make of. Intelligent and well-read, but didn't know what Alola is, and has no knowledge of Pokémon to the point of being very weirded out by them... He also initially seems to have a meek personality, as he chose not to speak or draw attention to himself until he got this new strange world figured out.
He was put in the care of guardians that have experience with strange cases - the ones also taking care of Ailey. However, he quickly gains back his old spirit as he comes to understand this new setting, and shows his angry and narcissistic personality instead, though he tries and keep a monotone and mature air to himself. He believes he comes off as a cool and collected mature person, but most people can tell he's a strange and disturbed kid.
After he turned 11, he was convinced to try out the island challenge to loosen up a bit. He reluctantly agreed, but uses it as a way to explore the islands on his own and stick his nose in many places it does not involve. He is fearless when it comes to situations, leading him to be very useful, and very likely to get hurt.
The child of Lysandre, a French aristocrat who visited Alola about 12 years ago and had a house built there. René grew up in Kalos, but was often ostracized for being a bastard aristocrat, let alone one with a bit of a strange appearance. He did somehow become acquainted with Yves though, an older boy who helped him out of some situations.
Lysandre eventually decides to send René away to live in the Alolan property, very much against René's will. In Alola, he's the one who's a "stick in the mud" and extremely resistant to changing any of his ways or engaging with any local. His horrible attitude gets the attention of Midzuko, who wants to try and change him and get him to loosen up, and the attention of Kai, who just wants to mess with him and cause scenes.
From a group of doppelgangers with Lysandre at the head of it. While still very "young", he was overly advanced and was able to take over the original before understanding exactly what the situation was. Becoming increasingly freaked out and confused by the situation he's in, he starts to cause a bit of trouble and nearly makes some mistakes that could risk the secrecy of the house...
...But "fortunately", Blazing's time travel causes some mess-ups across the timeline, dragging a few people from various points in history (and the future) to the modern times, including Ray! Though Orane is probably his real name, and Ray the name of the human original, but when found by modern Alolans he panics a bit and gives that name instead. His first thoughts would have been along the lines of "what if these are people that remember the original?", before learning the reality of the situation he's in now.
Now he doesn't have to worry about Lysandre murdering him for causing problems, and instead has to worry about how to prevent himself from getting caught, as he has no ideas what the ramifications are if he does... and he really does have an understanding that he did something quite immoral. At least the time travel explanation gives him a reason to be awkward, but the more he stresses, the more likely it is he'll be found out.