∞ BCE - 19-year-old Jan Arrah is sent back to the beginning of the universe. He exists throughout the time, watching galaxies form and die, slowly coming to build them himself over the millenea.
2981 - Jan Arrah is born mysteriously to a single mother on Trom, an uncivilized human planet.
2985 - 4-year-old Jan is the sole survivor of a planetary genocide by the Dominators, his powers protecting him somehow.
2992 - 11-year-old Jan first discovers his powers.
2995 - 14-year-old Jan joins the Legion of Super Heroes as Element Lad in their third recruitment drive.
2996 - 15-year-old Jan discovers a broader use of his powers during the Legion of Super Heroes battle in Earthwar, gaining greater range and permanency.
2999 - 18-year-old Jan expands his powers further; learning to manipulate his own body.
3000 - 19-year-old Jan is lost in a distant galaxy and sacrifices himself to save the rest of the Legion of Super Heroes. He is slingshot out of time, and forced to exist in deep space for a millennia, watching the creation of whole galaxies. He becomes the Progenitor, forging whole civilizations to work his god-like will. He is killed by Garth Ranzz to stop him from following them back to their own galaxy.
Ohhh... Element Lad. There are a lot of superheroes that are clearly invented by someone with a decidedly limited understanding of how science works (Stan Lee fameously admits that most of his creations don't actually make any sense at all), but the Legion probably has more than their fair share, since a lot of their formative issues were written by a 14-year-old. Element Lad is a pretty fantastic example of that. The ability to transmute matter is a pretty bonkers superpower, and Jan's wielded them in a pretty all-over-the-place fashion. The wide variety of interpretations of the character have given us a lot of different attempts to settle that power in a way that made a little more sense in the larger context of the team by building different types of limits, but we rather like the idea of leaning into the notion of his status as a sort of infant godling. To make that idea really take root, we've actually introduced the idea of him being a miraculous virgin birth, and with his survival vs the genocide of his people (although we're using the Dominators instead of the Daximites, as we're using them elsewhere.)
Also; we're not 100% certain exactly WHY, but Jan has actually become something of a gay icon over the years. There was even a story in continuity when his love interest turned out to have been a man taking a future gender-changing drug. That's not just cool because he's a classic character with a history of being queer, but also because it comes more from fan interaction than from any specific editorial choice. Definitely something we should include.
If you're going to bring up Jan, though, you HAVE to include the absolute greatest story he was in, which also probably also my personal favorite Legion story ever: 2000's Legion Lost. It's probably the single best pure science fiction story ever worked into a mainstream comics, and had some of the coolest character development in the entire run of the Legion. please, go read it before you read the nest paragraph.
Within the pages of Legion Lost, Jan sacrifices himself to save the other lost members of the legion, and winds up sent back to the beginning of the universe. He's forced to watch as whole galaxies are born and die, and eventually begins creating them himself. Jan actually becomes a fully realized god. It's maybe the single most satisfying villain turn ever, and it's even better because it pays off within the pages of a single limited series. This is SUCH a great character.