|This article is about a/an ally in Kamen Rider Spirits.|
- "Yuki Joji, a genius scientist, formerly a Destron executive officer candidate. Anything else you want to know?"
- ―Annrietta Birkin's first words to an amnesiac Riderman[src]
Annrietta Birkin (アンリーエタバーキン, Anrīeta Bākin) is an Interpol Destron Hunter and was the one who rescued Riderman after his miraculous survival. She later became a commanding officer of Spirits along with Kazuya Taki supporting the Kamen Riders' fights against Badan.