Jemin is the strong man for the Justice Machine, with enhanced strength and durability, and the ability to increase his size and mass. A family man and slow to anger, Jemin is exceptionally loyal to his teammates, seeing them as an adopted family.
The importance of family is a regular theme for Titan. Jemin's mother and brother shared similar abilities and were members of other incarnations of the Justice Machine. Jemin's mother was killed while on a mission with the Justice Machine. Jemin's older brother hated him, bullying him mercisslessy while they grew up.
After the members of Jemin's Justice Machine were declared traitors they covertly returned to Georwell to conclude their personal business. Jemin went to the home he had built for his wife and children, intending to take them with him back to Earth. Georwell soldiers were waiting in ambush. Jemin's wife sacrificed her life to save him, and their children were killed in the subsequent chaos. Jemin, in shock, grew larger than ever before, destroying the house and burying the bodies in the rubble. The stress of growing so large caused Jemin to collapse in unconsciousness. Eventually he woke up and stumbled, still in shock, to meet the rest of the team.
Once on Earth Jemin struggled to cope with his familie's loss, almost allowing himself to die in a fire. After being saved by Blazer Jemin slowly began recovering from his loss.
During Justice Machine's time at New Atlantis Jemin participated in their initial battle against Killgore, was one of the first team members to discover the conspiracy to replace the team with robots and participated in the effort to repel the Georwell invasion.