Ultra Boy got his powers from eating the meat of a "space whale" he was briefly trapped inside. He first encountered the Legion as a part of Leland McCauley's Workforce. In a relationship with Spider-Girl at the time, he as immediately smitten on seeing Apparition, as she was with him. Soon after, despite his incompetence in choosing of gifts and the dislike her mother took to him, they entered a relationship until her untimely apparent death at the hands of White Triangle Daxamites. After this, he quit the Workforce and took to hanging around the Legion.
After playing a part in the downfall of President Chu as part of the Rescue Squad, he was able to join the Legion proper; but suffered from infrequent, but debilitating, stomach pains - eventually revealed as Apparition's now-permanently phased body trapped inside him. Ultra Boy and Apparition were then among the Legionnaires trapped in the 20th Century, where despite the intangible Tinya's insecurites about their relationship they married, and Apparition regained a physical form by merging with Phase - revealed as her own second body from Carggite heritage she had been unaware of - before they returned to their home time.
There, they were absolutely inseparable for months. Eventually, Tinya decided to make a point of going on a Legion mission without Jo, to prove to herself as much as to him that they could survive apart. This led to her, Brainiac 5.1, Cosmic Boy and Monstress being stranded far from Earth as, while they were away, the Blight used the Stargate network to take over the planet, shutting the door behind them, while Jo was taken as one of the Blighted. Being confronted with her, as Saturn Girl and M'Onel freed the Doda, the Blight's slave transports, was enough to free him and he threw the Blight's leader, Atrophos, into an energy stream, discorporating him.
Shortly afterward, the Blight's damage to the Stargate network led half the team to be thrown through a Rift in space to a "Second Galaxy." Just as Ultra Boy was about to go nuts at the thought of never seeing Tinya again, she seemed to appear from the floor. However, this was actually a telepathic illusion on Saturn Girl's part, who "played" Tinya in an attempt to keep Ultra Boy sane. When her deception was discovered, Jo Nah initially ignored Imra, then they ended up passionately kissing. Confused, they broke off and were awkward around each other until returning home.
After being reunited with Apparition, however, their marriage came under strain after the extended separation, as she discovered a letter to Imra mentioning Jo's kiss with her, even as he and Imra realised that their kiss was borne purely out of confusion, and he misunderstood her relationship with Timber Wolf. In addition, Cub, their son which Tinya had borne while he had been trapped in the Second Galaxy, aged rapidly, reaching an apparent age of six years old after an experiment designed to retard his aging backfired. The tensions have not been resolved to date.
Powers and abilities
One at a time from super-strength, the ability to fly unaided, heat vision, penetravision, telescopic vision and super-hearing.