>>47155027They gave Rose a sob backstory where his father was a mine worker that died in a mining accident. This made Rose obsessed with finding alternate energy solutions. Instead of an energy crisis 1,000 years away, his motive became to create enough energy to power Galar for 1,000 years.
Rose is also said to be insane by Professor Magnolia. It's unclear if he was crazy before his father's death and his death just gave Rose a focus to obsess his unstable mind on. He knows his experiments could kill people but he calls them "necessary sacrifices for Galar's future".
Rose openly admitted to grooming Leon and other talented young trainers in order to have one of them catch Eternatus for him. Any mentor role he took on was a calculated move to use the person for their talents as a trainer. He tried and failed at doing the same with Ash.
Rose also escapes at the end of the arc, so he'll obviously appear again at some point. He's a much bigger scumbag in the anime.
