The Prodigal Children are a group consisting of heroes from various timelines and dimensions, picked for their unique talents and "natural" training. They are all prophesied saviors of Zeon, meaning that they are all Beorns.
Nobody really knows who came up with the idea to make the Prodigal Children, but they were obviously inspired by the meeting of Unten and Untina, and their motivation was obvious - to have a team capable of performing a Descension that had received the same training but had developed different skills. With this goal in mind, this mysterious person gathered several dozen "Prodigies" in a single room.
It's a miracle that none of them managed to kill each other in the subsequent brawl.
Eventually, their mystery patron showed up (in disguise, of course) and offered them jobs as part of the universe's fail-safe mechanism. If the whole of time and space was threatened, the Prodigal Children would be the first line of defense. And, by association, also probably the first to die. A lot of the "Prodigies" turned down this offer, for various reasons. But there were some crazy enough to take up the challenge.
None of the newly-titled Prodigal Children noticed at the time, but several Prodigies, including Unten and Untina, were absent from the meeting, even though they were among the most likely to accept the burden...