The Solens lineage was established by settlers on a recently colonised Mid Rim planet. Prant's parents are low-level administrative workers: not really wealthy or distinguished, dull and stifling just like all those who have learned to be content with what little they have, because little is all they are likely to get.
Bryrill Solen is a man of modest origin and no particular gifts. He is a bureaucrat of the lowest tier, the kind others wipe their feet on, and he seethes with petty resentment for it. Stability and appearances matter immensly to him, because he possesses no real power. Around him, colleagues climb the career ladder, whereas he has occupied the same position his entire working life.
When his oldest daughter, Agny Solen, is accepted into a military academy (= a real social elevator) and achieves what he never could, Bryrill is forced to confront something intolerable: how thoroughly his stupid chud son resembles him. The same timidity, same instinct to avoid conflict and settle for what is given. And he grows angry. So when he lashes out at Prant for his lack of ambition, his passivity, he is lashing out at himself.
Well, Prant doesn't understand this, he just internalises all of it. Which is why he, too, applies to the same academy, despite possessing neither the temperament nor the desire for it. He simply wants his father's respect. When he fails to meet the required standards (physical training, for instance), it only reinforces the belief he already carries: that his father is right, that there is something fundamentally wrong with him.
Around this same time, Prant's relationship with his sister begins to fracture. By the time the Empire is established and he meets Graft, they barely communicate. Agny is the odd one in the Solen household, almost forcefully bright. The Solen home is a quiet, airless place; confronted with this, she decided early that if no one else would lift the mood, she would. Her cheerfulness is real, but it is also a performance, a deliberate refusal to sink. She becomes the family's emotional counterweight, and it exhausts her in ways she rarely lets anyone see. The academy recognises her potential immediately, and she thrives there, building the connections and reputation that will carry her forward. Truthfully, Prant envies her. She carries none of the hesitation that weighs him down, and he can't decide whether that makes her admirable or insufferable.
His mother, Cazra Solen (formerly Cazra Birgid), is Serennian - a fact that later earned Prant a lot of side looks from his colleagues on suspicion of separatist connections. Cazra is not unkind, but she is a little bit too distant. Her own upbringing was rigid, aristocratic in form if not in means; children were expected to be self-contained, and affection was a currency spent sparingly, if at all. She loves her children, she really does, but she has never quite known how to show it. There is, too, a quieter tragedy in her: an interest in the arts that she never had the permission to explore. As a young woman, she sketched, nothing ambitious, just small studies of the world around her. She had an eye for composition. But life on a colony world left no room for such things. Bryrill considered it frivolous, and Cazra, already accustomed to self-denial, let it go without argument. When the Clone Wars broke out, she lost her job and fell gravely ill, eventually confined to a hospital bed.
Prant is, unambiguously, a mama's boy. His closest relationship is with her, though they never speak of their feelings. In the Solen household, such things are simply not done. No one really says 'I love you' or hugs. Prant reaches adulthood fundamentally untaught in the language of physical affection. Small wonder, then, that he remains so reluctant to initiate contact; he was never shown how to do so properly.
When Cazra is dismissed solely because of her origins, Prant becomes fixated on bureaucracy, on the absolute necessity of following rules. She was let go, he reasons, because of some legal loophole, some procedural gap that could be exploited. Therefore one must work in such a way that there is nothing to pick at. It's better not to stand out, not to draw any negative attention.
But years later, intelligence officer who watched his mother be discarded recognizes someone else the Empire is preparing to discard.