Queen Belthera was the ruler of an realm located within the Nanoverse known as the Sorcerer's World. The Atom, Donna Troy, Jason Todd and Bob the Monitor entered Belthera's realm while searching for their missing colleague Ray Palmer.
Belthera used her magic to take control of Bob the Monitor, and stole the Atom's Bangstick. She then imprisoned Donna and Jason while declaring her intent to take control of the Multiverse.
Kyle Rayner, now a Green Lantern again, arrived in Belthera's realm and helped free his allies from her control.
Belthera eluded capture however, and escaped into the byways of the Multiverse via a mystic portal.