John Grimm is the fraternal twin of Dr. Samantha Grimm. Their parents were geneticists and began teaching their children their trade at an early age. Early in their childhood their parents were killed in a tragic accident. The siblings were outside in the playground, when an explosion ripped through the lab killing their parents. John would never forget the screams of the people trapped inside. As a result of the accident, John and Sam were bounced around from foster home to foster home until their grandparents could finally get custody of them. Both have a knack for genetics, but Sam is the only one to follow this path. John decided he wanted nothing to do with the research that killed them and joined the military.
At the age of 18 he joined the Marines, quickly moving his way up the ranks and is recruited for the elite Rapid Response Tactical Squad. Where he met his commanding officer, Sarge, a man who would do anything to succeed. Although he hasn’t spoken with his sister in years, he kept up on all of her research and how she was doing. She was the one weak spot for the hardened Marine. He was tagged with the nickname ‘Reaper’ by his squad mates and quickly moved his way up to second in command of his unit.
In 1998 Sarge informed the squad of a special program they had been volunteered for. It was supposed to make them faster and nearly invulnerable. This program was being operated by Donald Lydecker, head of the MANTICORE Corporation. After finding out what the experiment entailed, John decided that he didn’t want to take part in it, but was informed that refusing wasn’t an option. They held his sister over him as leverage and he reluctantly agreed to take part in the experiments in order to keep her safe. He was given different injections that allowed him to perform under various conditions. He was finally injected with something called Chromosome 24. Unfortunately, his body, like all others before him, began to reject the treatment after a few days. Lydecker ordered that he be Turned by a rogue vampire he had working for him because he didn’t want to lose one of his best test subjects.