Obsidian is the code name of Todd James Rice, the biological son of Alan Scott (the Golden Age superhero Green Lantern) and the Golden Age villain known as Thorn. Todd was raised in an abusive adoptive home in Milwaukee, Wisconsin. He found out in his late teens that he had a twin sister, Jennie-Lynn Hayden, alias Jade. They met, discovered they both had superpowers and, operating under the assumption that Green Lantern was their father (which they did not know for certain at the time, but did eventually learn to be true), decided to follow in his footsteps.
Jade and Obsidian became founding members of the hero group Infinity, Inc, which comprised those who continued the legacy of the JSA. He served with this group for its duration, then continued to partner with his sister. He was also briefly affiliated with the Justice League.
Obsidian apparently inherited schizophrenia from his mother, Thorn. However, his connection with the shadow realm which gave him his powers and the experience of seeing the blackness within many other souls caused him to go gradually insane, and after many of his team-mates were killed and the Justice League of which he was a part was disbanded, he began a sort of revenge campaign against both of his fathers - biological and adoptive. Corrupted by Ian Karkull, Obsidian turned evil, using his shadow powers to spread darkness over the entire world. Obsidian had a conflict with the new JSA in Milwaukee which was ended by a sacrifice on the part of his adoptive father James Rice after a drawn-out battle with Sentinel, He was defeated by his father. Obsidian retreated to the Shadowlands, the other dimensional plane from which he derives his powers. Later he joined the mystical villains Mordru and Eclipso to seek vengeance (unsuccessfully) on Green Lantern and the JSA. Following his defeat, Obsidian was cured of his mental imbalance.
After being cured, Obsidian retired. It was during this time that Todd finally came to terms with the fact that he was gay. He met and fell in love with Damon Matthews, an assistant district attorney who works with the vigilante Manhunter (Kate Spencer). Todd's powers went dormant during most of this time, but they returned, following the death of his twin sister Jade during Infinite Crisis. He has since then returned to being a superhero and is still dating Damon happily.