Krysta, the Alolan Vulpix, and Pyrra, the Kantonian Vulpix, haven't always been conjoined. They hatched at about the same time in different litters across the Alola region, though Pyrra is a little older.

Krysta grew up on Ula'ula Island. Her home were the icy surroundings of Mount Lanakila, the roughest and coldest mountain in all of Alola. She spent a happy cubhood and loved playing with her several littermates. One day they ventured a bit too far and ended up getting lost in the mountain's cave system. Falling rocks ended up hurting Krysta's rear legs so badly that she could no longer walk. Her siblings alerted humans in the near Pokémon League and Krysta was taken to a Pokémon Center. She recovered from the shock and pain, but something was still wrong with her hind legs. A Pokétherapist was called to help her regain mobility again, unfortunately an unsucessful attempt. After some discussion it was decided to bring Krysta to a lab and have scientists fit some wheels on her to aid mobility.

Pyrra on the other hand lived in the Wela Volcano Park of Akala Island, the single cub to a pair of Kantonian Ninetailes that a visiting trainer brought over from Kanto and abandoned there. She was born without hind legs and had a rather short, stubby tail for a Vulpix. That didn't stop her from exploring the steep and oftentimes rough surroundings though. The trial site atop the mountain quickly became her favourite place, she loved watching trainers take on each other there. After one such battle an older trainer spotted her on his way back down the mountain and took pity on her situation. Over the next several days he would gain her trust with a couple berries and eventually convinced her to come downhill with him. The old man ended up bringing her to the same laboratory Krysta was in, hoping she could be helped there and then possibly rehomed in a safer environment than the volcano park.

It was in that laboratory that Krysta and Pyrra met. They were first put in adjacent areas and quicky bonded with each other, to the point that the lab assistants let them share the same cages. Shortly after Pyrra's arrival the lab was bought up and the new owners turned out to be rather unethical in their experiments. One such horrible experiment was conducted on the two Vulpixes, resulting in their hind legs getting removed and them being conjoined. They were still in recovery and trying to learn how to walk anew when Bennet rescued them from the lab. He took them in and spent a lot of time to gain their trust and nurse them back to a healthier state. (Yes, Jaari got very jealous.)

During a later visit to Mount Lanakila with their trainer Bennet Krysta and Pyrra learned that most of Krysta's siblings and family were still living in the wild around the mountain. They didn't forget her and learned from the incident, most of them having become Ninetailes to have a better chance at survival.