Got frustrated and skimmed through it… can somebody tell me what happened to the cousin ...

If you mean Vena and her stepdad. The emperor was in love with her mom and despite her father and the emperor being friends at the time, he exiled him and forced her mom to marry her stepdad while pregnant with her. Vena heard years later from him after he lost a ton of his status talking about how MC is half commoners blood cause he assumed since she was illegitimate it had to be with a commoner. Her father ran off after his prison sentence and him slipping away, and ended up in the North (where MCs dad is the Duke), and Vena spread the rumors that MC was a commoner so she was imprisoned too then let to escape to the North. Yada yada a whole lot of revenge by the father there for ruining his daughters childhood but they ended up later on having to go before the throne and testify that they heard the rumor right, and then the Duke was revealed as her father. Vena got upset but they were both sent back to prison, and Vena ended up being executed after she was silenced. Her stepdad got a life sentence cause he was already insane after what the Duke did to him

If you mean the male cousin he’s running the Barony just fine cause him and MC are friends. He also helped with revenge a bit in the end there

Thank you bestie