Omicron was an artificial intelligence created by a race called the P'Shem to explore the Cardiff Rift. It had mapped a model of the universe onto the quantum tesseract fold inside its body. It could shapeshift.
The robot emerged from the rift at the Queen's Arcade shopping centre. He revealed himself to be an Omicron when the Harrowkind attacked the centre, he transported them into his databanks, with the intention of releasing them somewhere else. Vox, knowing that it had information on his people, the Sanctified, and knew of the real reasons as to why they hunted him, was forced to destroy the Omicron before Torchwood could probe him. (COMIC: Rift War!)