Ultra Boy stars in the Legion’s first “full-length” story, which is also the first issue of Adventure to feature only one story, in issue 316 (Jan 64)
Jo Nah’s origin is shown, getting swallowed by a space whale. I guess that’s the best origin one is likely to get with the name Jo Nah.
The Legion discover that he has a criminal past on his home planet of Rimbor, and joined the team under a fake name. So none of them questioned the name Jo Nah. Guess the space whale made it plausible.
Ultra Boy is expelled from the team, and goes on a rampage. Phantom Girl is devastated, and the romance between the characters builds out of this story.
Jo joins a group of space pirates, as the rest of the Legion try to hunt him down. Chameleon Boy actually manages to track him, but Ultra Boy escapes.
Phantom Girl also finds him, remembering a secret place he had told her about, but shows up just as the space pirates arrive.
She gets brought aboard their ship with Ultra Boy, who almost immediately turns on the alien raiders and apprehends them.
We learn that it was all a ruse concocted by Ultra Boy to be able to get close to the pirates. He had planted false information about his past, intending to be expelled. Once the Legion discover this, they welcome him back.
Aside from setting up the Ultra Boy/Phantom Girl romance, Edmond Hamilton’s story also gives Jo the semi-shady background on Rimbor that would be a major part of his character as the Legion continue through the decades.
One final note about this story. Proty II is introduced, again a pet of Chameleon Boy. We see, for the only time, a statue of the original Proty.
One cannot help but fear that Cham simply got a new Proty to hang onto in case he or some other member of Legion died, and then they would just sacrifice this one to bring the dead member back.