Blackjac Mac was created by John Ostrander and Timothy Truman in the comic book Grimjack.
Blackjac Mac was the son of Mac Cabre, one of seven kids. He grew up in the slums of Cynosure the interdimensional city. Mac Cabre was a small time hustler who regular beat his wife and kids. Mac Cabre would eventually fall in with the former gladiator turned crime lord known as the Dancer. Mac Cabre’s standard of living would go up, but not his family’s.
Eventually, Mac Cabre would go to far. When Blackjac tried to protect his mother, MacCabre beat him into a coma. Blackjac would wake up days later to find his mother dying. When she passed away, Mac Cabre used the Dancer's contacts to sell Blackjac to the Arena.
There he would be trained as a gladiator by Uncle Willy. Blackjac was consumed with rage and was known to go berserk during training. This distressed Uncle Willy who believed Blackjac was going to get himself killed. Uncle Willy would tell this to Grimjack, who was the best fighter in the Arena.
One day during training, Grimjack picked a fight with Blackjac. Blackjac went berserk, but Grimjack easily handled him. However, Blackjac was able to clear his head during the fight. Then Grimjack allowed Blackjac to cut him before Uncle Willy stopped the fight.
When asked Blackjac asked why Grimjack allowed himself to be cut, Grimjack replied that the gladiator’s real enemy was not the other gladiators but the audience. Grimjack said, “Your life, my life –are worth nothing except to give them a quick thrill…When Uncle Willy told me about you, I just had to do something otherwise those bastards were going to have a cheap, easy death. I couldn’t stand that.”
Blackjac decided then and there he wanted Grimjack as a friend.
Eventually, Grimjack would be freed from the Arena. Blackjac would not see him until the Demon Wars. Hell would invade Cynosure and the city would need all the fighters it could muster. Blackjac would join up and serve beside Grimjack.
After Hell was defeated, Blackjac would start up his own private mercenary army. He would also begin a relationship with Goddess a woman who was quite literally a goddess. He would continue to aid Grimjack.