Topaz is a character from Sonic X. She is a GUN agent and the human partner of Rouge the Bat. Though at first the regimental Topaz disapproves of the scheming Rouge (who keeps calling her an old lady), the two become friends fast. Their main assignments involve striking at Dr. Eggman and retrieving the Chaos Emeralds, as well as serving as envoys between Sonic and his friends and the government.

Topaz also seems to have romantic inclination towards Chris Thorndyke's butler, Mr. Tanaka. The two have worked together on several occasions, and when Topaz lost in a tournament over the red Chaos Emerald, Tanaka gave her a necklace, a sign of a growing relationship between them.

Topaz's outfit is very similar to that of the character Virtua City's female protagonist Janet Marshall from Virtua Cop 2 and Virtua Cop 3 and Anne Lewis from Robocop: The Animated Series.

Topaz still makes a few appearances in the Sonic X comic book, being once again, Rouge's partner, and their relationship is the same as in the show.

Topaz's last appearance was when Sonic and his friends were returning home. She said farewell to her partner Rouge, who gave her a ring as a goodbye gift. Although Rouge usually covets any jewel she comes across, the act of giving Topaz a ring shows that she values Topaz more than jewelry. A tear is noticeable in Topaz's eye when Rouge waves good-bye through the portal.