Lothar Frey is important only because he happened to be one of the perpetrator's of the Red Wedding , one of Game of Thrones' most horrific twists. At Robb Stark's wedding in season 3, the Freys collectively turn the wedding into a bloodbath. That is how Robb himself dies. It's also how Talisa Stark, Robb's pregnant wife, dies. And who killed Talisa Stark? Lothar Frey did, right after he stabbed the growing baby in her stomach. (It's called the Red Wedding for a reason.)