Vulcan was one of the few krogan to be born on Tuchanka after the genophage was occurred. After his first year, he was separated from the female clan and placed into the male clan. His father, Torr, happened to be the leader of the clan, and he was more than proud of his accomplishment. The clan, Skair, ended up falling apart.
Eventually came the time for Vulcan's rite of passage, the time for him to prove himself to the rest of the clan; Whom of course always looked down at him. He faced the rite alone, no one wanted to risk their lives for the little runt. By the last day, he finally returned. He had lost a finger, but gained a varren ally.
Vulcan spent decades of training, everyday he would go through a rite and kill fauna. Eventually the shaman decided that Vulcan was worthy, and that if he could kill him in a fight to the death, Vulcan would get his position. He defeated the shaman, but when he returned, his clan had been destroyed. He was then driven away by the clan that had defeated his own.
Eventually he was noticed by the Blood Pack, who offered him to join. With nothing left on Tuchanka worth his while, he decided on going with the mercenaries. He was assigned his own squad in the pack, consisting of vorcha. During this time he knew he wasn't meant to lead, especially considering he would purposely kill the pests on his team. He spent a couple of years with the pack, and eventually decided he wasn't making enough credits. He then became a freelancer and lived on Omega.