After the events of using her Chaos and almost killing her younger brother, Violet, in the process, her fathers Hau and Gladion tried everything they could to research up on Chaos energy.
It was sort of a dying myth, that there would be people who would have Chaos energy. It was also uncommon for people to have Chaos energy in the first place - it was mostly a known fact that Auras were the more dominant ones. But Hyacinthe had Chaos and there wasn’t anyone that they know of in Alola that was a Chaos Guardian or expert.
Gladion went to his sister, Lillie, and also Guzma for help in this matter. While Hau went to his grandfather, Hala, for any sort of information about Chaos.
Fortunately enough, Hala managed to find some old notes and journals about Chaos energy, as well as the last known Chaos Guardian. However, no one really knew where the current Chaos Guardian went.
Hyacinthe was still locked up in her room, afraid to do anything in fear that she would hurt her family with her Chaos. Then she overheard her fathers talking about information they found out about it, as well as a Chaos Guardian. Curious, like always, Hyacinthe snuck out of her room after everyone went to bed, and took the old notes and journals from her fathers’ work room. She has found the answer she had been seeking and decided to head over.
However, lucky for Hyacinthe, there actually was someone in Alola that was the current Chaos Guardian: Guzma. He approached Hyacinthe when she was setting off to her great-grandfather’s place and immediately sensed that Guzma held the same powers as hers. Which was weird considering in the journals, it was said that the current Chaos Guardian was missing.
He wasn’t missing. He was just trying to get away from the responsibilities of being a Chaos Guardian.
So news spread that Guzma was a Chaos Guardian and Gladion and Hau confronted him about it. Guzma explained his situation and told them that being a Chaos Guardian was not what it’s cracked up to be. It’s completely different from being an Aura Guardian being that Chaos looks after death and destruction. If the Chaos user isn’t strong mentally and emotionally, becoming a Chaos Guardian will be extremely tough and could break the Chaos user down.
Hyacinthe wanted to at least try and control her powers, she didn’t care about becoming a Chaos Guardian. She never asked to have Chaos energy in the first place. She begged him to teach her how to control it so she couldn’t hurt anyone anymore. Guzma caved and taught her all he knew about Chaos energy and controlling it.
The training did help Hyacinthe get out more and she ended up reverting back to her old self at times. However, when she was off training by herself (Guzma went off to do some sort of errand/mission work for Professor Kukui), Violet came out to watch. He missed spending time with his sister. Except Hyacinthe didn’t want him anywhere near her when she’s training because she’s still working on controlling it. But Violet’s stubborn and wanted to stay. Things ended up happening and Hyacinthe lost control of her Chaos again and it BARELY struck Violet. It was a close call though like it did graze Violet but thankfully it wasn’t like the first time.
Hyacinthe, completely freaked out, yelled at Violet for not listening and ran away. This event happened a year after their great-grandfather’s, Hala’s, passing. It was also after when Hyacinthe found a letter Hala had a question that he was seeking to answer but could not.
After this incident of losing control, Hyacinthe left her home to not only find the answers but to try and manage with dealing with her Chaos on her own, away from her family so she couldn’t hurt them.