Little is known abouth Blithe's past.
It is known that to become an Earth-Born Angel, one must sacrifice themselves for one who is beyond hope and merge with them into one being. But Blithe doesn't seem like someone who would save anybody. In fact Blithe was a valued servant of a vampiric demon called the Carnivore. At his behest, Blithe used her psychic light powers to illuminate repressed memories in the heartbroken male-female merged Comet, and make his female form fill with feelings of hate and abandonment. This turned Comet into a very angry angelic centaur. Blithe and Comet both attacked the third Earth Angel, Supergirl, but Supergirl was able to defeat them both. However during the battle, Blithe was crippled by avalanche. She begged her master Carnivore for help, but he scoffed at her, calling her a crippled firefly. Blithe was in love with Carnivore, and this rejection drove her over the edge. Still able to fly, she flew to where scientist were keeping the evil half of Matrix, and merged with it, healing her crippled form and giving her stronger powers. She then teamed up with Comet and Supergirl, and the three fought and destroyed the Carnivore by combining their angelic powers of Love, Fire, and Light. Blithe realized that she had feelings for Comet, and didn't care which form the dual-gendered Comet assumed (which hinted that Blithe is bisexual). She was seen fighting alongside Comet during the period where Linda Danvers was separated from her Angelic half. It is assumed that the two are still together.