Err, anyway, here's a full 3k words on Vierce's background with Seven Deadly Sins and Seven Virtues.
Conveniently, this corresponds to the seven original members of the Ridgeside crew (Kirsk was only around the edges)…and in fact, the core never varied much from seven. No game spoilers.
(Edit: For context, Vierce grew up on an occupied world; the only plot-relevant stories I've published to date that really touch on his neighborhood crew are Teachers and Heroes
, set in 4 BTC, or five years before this sequence begins; and (Bad) Memories
, which takes place early in 6 ATC, between this sequence's Courage and Wrath/Justice.)