Jupiter (real name Giulia Firsov) held feelings for her boss for quite some time, though she was fairly certain that Cyrus didn’t, and would never reciprocate. All the same, towards the end of the DPPt plotline, when it looked like Team Galactic’s plans would be a success, Jupiter decided that it was now or never and she might as well see if Cyrus was interested. Surprisingly, he accepted and agreed to engage in a one-night-stand, no strings attached. In Cyrus’ perspective, because he was about to remake the world into his perceived ideal image, that would require sacrifices from his commanders, so he would indulge in their ‘last wishes’ even if he did not understand the appeal. As such, the feelings were one sided on Jupiter’s part, but she was never under the illusion that they would be anything but one-sided. What she didn’t account for was not only to have her boss disappear into the distortion world, not only for Team Galactic to fall apart and for her to be arrested, but on top of it all, find out that she was pregnant with Cyrus’ child after being arrested.
Callisto Firsov was born in the Sinnoh Regional Penitentiary and his mother wanted very little to do with him. To Giulia (no longer Jupiter now that Galactic was done for), Callisto was just a reminder of her failures and mistakes that led to her incarceration. When he was around 18 months old, Callisto was placed into the foster system, where he would spend the remainder of his childhood being bounced from foster home to foster home, never staying at the same place for more than a few months. While some of Callisto’s foster families were genuinely invested in giving him a good home, plenty were far from ideal, and he learned from a young age that trusting others, especially adults, was dangerous and that he was better off taking care of himself. This also led to Callisto become involved with illegal and dangerous activities, including joining a gang when he was in his mid teens. Callisto skipped school frequently and had little interest in considering future careers aside from keeping himself afloat. He befriended a few pokémon, most significantly his starter and partner, Maestro the Skuntank, but many of the pokémon battles he engaged in were the kind that weren’t just for fun or sport, but posed a serious danger to both the trainer and pokémon. Callisto never saw himself having any other life than his half-on half-off the streets lifestyle living day to day, but following a run in with the law and a betrayal by a former ally that left him almost dead, he decided to turn his life around.
Callisto may not have regularly attended school growing up, but he was still quite a smart kid, so by buckling down and studying, as well as getting help from a local organization that supports people like him looking to help themselves, he was able to get in with a scholarship to the local Hearthome Community College, where he began to study social work, in the hopes of helping those with difficult backgrounds, who were let down by the system, like himself. One of his preferred study spots as a student (when he wasn’t sneaking in flashcards to one of his part-time jobs) was in the library at Hearthome Institute of Technology, one of Sinnoh’s top universities. He found that the environment there tended to be quieter and better for his own studying needs, even if he wasn’t a student. It was while studying there one afternoon that he first met Ceres, who was a student at HIT majoring in mathematics. The two struck up a conversation and hit it off, exchanging numbers and starting a ‘study buddy’ relationship that didn’t take too long to turn romantic. When Ceres found out that Callisto had no idea who his birth parents were, she encouraged him to track them down, so he could at least know and the two were pretty surprised to find out that his mother had been a top member of Team Galactic, especially since of Ceres’ fathers also used to be a member (Sasha Severny aka Saturn), though she encouraged her boyfriend to keep that a secret.
Callisto decided to send a letter to his mother, who was out of prison at this point and living in Solaceon, just to reach out and let her know what was going on his life, but also since he was curious about his father, as he wasn’t mentioned in any of the records he and Ceres managed to access. Giulia still wasn’t very interested in meeting her son, but she did tell him that his father was former Galactic leader Cyrus. This lead to a whole other round of searching as Callisto and Ceres tried to figure out what had happened to the man, eventually tracking him down (through dubiously legal methods) to Twinleaf, where he was living with his sister and brother-in-law. Callisto reached out to Johanna about who he was and if she and her brother were at all interested in keeping in touch, whereupon Johanna paid for tickets to get her newfound nephew (and his girlfriend) out to meet her. Cyrus was surprised but fairly accepting that he had a son, and though Callisto never grows extremely close with his father, he does form a strong relationship with his aunt, uncle, and cousin.
Callisto completes his degree and gets a job working for an organization that helps support children in foster care (keeping siblings together, trying not to move them around as much, finding good foster parents, etc). Ceres graduates with excellent grades and starts out as an information scientist for a local research group, though later decides she’d rather pursue her childhood dream of becoming a professional pokémon trainer, which she excels, eventually becoming the Hearthome Gym Leader with a specialty in poison-types, though she still keeps up with her passion for numbers as a part-time job (and by incorporating math puzzles into her Gym design). Callisto and Ceres are eventually married and have a daughter together in 3637 named Proserpina (or Pina for short) and are both very happy!