Epsilon

Epsilon is a beautiful female robot that moniters Metro City's weather and marine animals, and is closely allied to Astro. Like Astro, she believes that war isn't the only way for humans and robots to get along. She is hinted to be Delta's sister and comes from Australia.

She is apparently the successor for Photar in the 1980's series, due to many similarities.

She was defeated by Pluto

She is hinted to be the sister of the robot Delta

Appearances in "Astro Boy" 2003 series
In the 2003 series, she was a close friend of Astro that could predict the weather and was a nominee for the Robot of the Year award.