When Lilith Mother of all Demons was freed from her mystical prison Leviathan and summoned her Lilin, their presence weakened the dimentional fabrics. This led to a reality rip to occur in Phoenix, Arizona, in a rundown building's basement. This rip allowed a hive thinking bacteria known as the Viral Swarm to enter Earth 616. In the Viral Swarm's home world they were the dominante lifeform as they had fed and consumed all living beings are energy forms. The Viral Swarm seeing the reality rip into Earth 616 saw this as new life energy to feed on.
The basement in Phoenix, Arizona was being used by several homeless people as a shelter. The Viral Swarm bacteria seperated and in doing so found amongst the various homeless people individual hosts. This particular part of the hive bacteria would be the only one that did not pick a homeless person that was inside the basement. It was instead drawn to a bitter and angry woman named Maggie who was just outside the building. This aspect named itself Macabre and became the leader of the group.
Macabre was created by Roy Thomas and Andre Coates in 1993 and first appeared in The Secret Defenders # 1.
Powers Granted To Host
Now that the Viral Swarm had infected the host body, it used its power from its original world to transform the angry human into a Superhuman, the baterica would allow the host to represent swarms most deadly aspect it's ability to bring death. This allowed the human host Macabre to kill people with the slightest touch.
She also had the ability to heal and create youth in others. This among the Swarm's own ability to drain human lifeforce, have a joint mind giving them a supreme hive intellect made them a deadly team.