He is a psychopath obsessed with bombs, who worked for the IRA. He was in jail in a castle prison in Northern Ireland, but he managed to flee from there, killing a guard and his cellmate in the process after turning a toilet into a bomb.
Now he is hellbent on revenge, because his pupil Liam rebelled against him because of his obsession with bombs and his lust to detonate them. He even wanted to detonate one behind his back, which would have killed lots of civilians. When Liam found out about it and wanted to stop him, he became mad. He still had to detonate it in his lust and also detonated it prematurely killing his own men in his cell on the way, including his sister, Liam's girlfriend. It lead to his imprisonment for life and to the expelling from the IRA.
When he arrived in Boston, while working as a freelancer, he finds him on TV, now with a new identity, James Dove, and is determined to carry out his intentions blaming him for what happened, and destroy everything he loves there and kill everyone he loves on the way piece by piece.
He dies, when his home in Boston, which is in a ship, explodes.