O'Riley was first mentioned in a list of aspects of the Eternal Champion given in The Dragon in the Sword, in which she was named "M'v Okom Sebpt O'Riley, Gunholder of the Qui Lors Venturers". Her first actual appearance, though, was not in a Moorcock novel, but in the graphic novel Elric: The Balance Lost. In it, she was fleshed out as the Captain of a crew of Chaos Engineers who manned a Scaling Ship called The Mandelbrot Sex. Due to the destruction of the Cosmic Balance, her world was destroyed by the Straight Arrow Fleet of the Singularity, and she was its sole survivor.
Elric: The Balance LostEdit
She fled to Eric Beck's world to save him from the forces of Law there, to help him retrieve his Black Sword Murakamo-No-Tsurugi, and to ensure he followed down the path of his destiny as the Eternal Champion. Unfortunately, it cost her her life, as she was forced to sacrifice her own soul to power the Banning Gun to prevent Eric's brother from killing him, and she died in his arms. Eric took her Banning Gun, and wielded it in battle for a time, until he ultimately discarded it just outside the walls of Tanelorn. He related these events to Captain Billy-Bob Begg, who apparently knew O'Riley, and was surprised she'd survived the Venturers' destruction.