“Depending on who you place in the same situation, the characteristics of said incident change kaleidoscopically. In other words, there is one incident. However, there are as many stories explaining it as there are people involved in it.”
Vino, or Claire Stanfield, was raised by the father of the Gandor brothers. As a result, he was as a brother to them and as such, part of the family. And in reality, you could call him the fourth brother of the Gandors. I heard he was taken in by a circus afterwards. Thanks to his hard work and superhuman talent, he was able to obtain beyond-human strength and technique. That’s probably also coming in handy now that he has become an assassin.