Jigsaw

William "Billy" Russo is a former Special Forces soldier who had become a close friend of Frank Castle. Russo became a part of Cerberus Squad under the leadership of William Rawlins, assisting in assassinations of high value targets. Upon leaving the Marines, Russo was funded by Rawlins and became the founder and CEO of Anvil Securities, training soldiers for Rawlins' needs.

Learning of Castle's return as the Punisher, Russo was recruited by Rawlins to assassinate his former friend, using Dinah Madani to try and learn of Castle's whereabouts which eventually exposed his involvement in Cerberus. Fearing he would soon be used as a scapegoat and blamed for all the crimes, Russo betrayed Rawlins, allowing Castle to kill him, before Russo had a furious showdown with Castle, that led to Russo's handsome face being damaged beyond repair.