Okay so, I know this is kinda crazy... Because it's fucking Berton Varrish, BUT- I have a theory.
We all know that Signets are formed based on what the rider needs most, Xaden keeps secrets, Violet needs to do the absolute most to protect those that she loves, etc.
Since Varrish's signet is Weakness Reading, that already says a lot about his character - and I believe it could go two ways.
1. He is a sociopath, genuinely doesn't feel or understand emotions beyond psychology textbooks - and with how brutal Navarians tend to be, it makes sense that he leaned into the violence, since he felt no guilt for it. The weakness reading gave him an upper hand, which many sociopaths wind up wanting - in the name of self-preservation. Which is a cool concept, to think that certain disabilities and mental illnesses could reflect on someone's Signets. Like Jeremiah, who was intinsic - which could easily be linked with feeling a sense of insecurity, anxiety, or self-consciousness.
2. Assuming he's like many decorated riders - joining the quadrant due to family ties - his parents could have very well been a lot like General Sorrengail. Well masked, refraining from displaying emotions, hard-headed, and a little cruel. If he was raised by older riders, who believe emotions to be weaknesses due to their time in the Wings - then their beliefs would have rubbed off on him.
He was described as being smaller than Colonel Aetos, who was only a little taller than Dain - so around 5'10-6'0. And while being shorter than 5'10 isn't exactly an issue, with him being a little on the thin side after years in the service - it would be understandable to assume that Varrish wasn't the strongest cadet when he attended Basgiath. The fear of showing emotions, and having weaknesses - along with not being the strongest - could have led him to developing Weakness Reading just for a better chance of survival.
It's honestly cool that even without being directly told, us as readers can develop even more understanding and depth for smaller characters - just based on the rules of the universe.
