Zac Mark II is the secondary undertaking by the remaining members of the Zaun Amorphous Combatant team. After unsuccessfully capturing the original prototype, a second was made. Zac Mark II was different from Zac. The original chemicals used were scarce, and similar ones had to be used. After several failed experiments, they managed to create a small, dark black blob, like an inkblot. The exception was that it moved, and it moved with vengeance. Zac Mark II was raised by the facility, trained by the facility, and educated by the facility. He was taught how to be a weapon.
Back in Zaun, everything was fine now that Zac was on the streets, but the introduction of Zac Mark II caused a catastrophic chain of events. But the most concerning was Zac Mark II's attempt to teach the original Zac how to be what he was designed to be. Zac, being the kind child he was raised as, fought Zac Mark II with every ounce of his strength, but they are near equals. A fierce rivalry was born between the two, and Zac gave the imposter the name, "Jac."
"Every school has a bully, and our bully is Jac."