So suppose Nala Se (kaminoan cloner from the bad batch) wanted revenge on the empire for destroying Kamino, she got a hold of a spartii clone cylinder, and a severed left hand frozen in carbonite as a trophy (of a long dead tapani saber rake) and the hand belonged to an almost legendary / wundetkind jedi (lost it shortly after being knighted when he was over confident) from just after the high republic period. That jedi had gone on to become his era’s master of niman. And all of that ties into the actual back story of Kelitah Laterius.
Suppose Nala Se wanted to create a living weapon to kill the emperor and vader, and she could flash program the clone Kelitaah (note the extra “a”) Laterius with generic jedi knowledge so that he came out of the tube as jedi career, jedi knight (quick path to power) with clone veteran (because she was heavily involved in the jango clones, so she could have flash read one).
Character progresses from there naturally, build to come. Probably encounters and gets some training from luke skywalker after rotj, but it’s more peer to peer training.