First Appearance: Citizen V & the V-Battalion v1 #2
(referred to) (July 2001).
Appearances: Citizen V & the V-Battalion v1 #2 (referred to).
The Golden Sun was Kenji Sabuki, a member of the V-Battalion. Her mother was the Golden Girl (II). Her daughter is Ameiko Sabuki, Goldfire, a member of the V-Battalion until very recently, when she died.
The Golden Sun is described as having "died in battle" when Ameiko Sabuki was only 5 years old. Since Ameiko is currently 21, that puts Golden Sun's death at 16 years ago.
Golden Sun's powers, like her mother's and her daughter's, were most likely solar-related.