From Cassius Comics

A semi-sentient cosmic force native to the Microverse, the Enigma Force evolved from the energy contained within the fabled Sword in the Star. The Enigma Force frequently sent the Uni-Power into the 616 Universe to transform various mortals into Captain Universe, working through them to combat menaces that could threaten their worlds, and by proxy, the Microverse itself. The Enigma Force eventually became corrupt and attacked the Microverse, but it was defeated by the sacrifice of the dimension's native warriors, the Micronauts.