Katma Tui was born on the planet Korugar; the same birthplace as Sinestro. After Sinestro lost his Green Lantern status Katma Tui was his replacement.
With her Power Ring she shares similar abilities and powers as all other Green Lanterns such as flight, energy projection, force fields, and Multilingualism.
She was also involved with John Stewart's Green Lantern training. She was married to John Stewart for a brief amount of time before she was killed by Star Sapphire.