Atsuko Sasaki

Atsuko Sasaki (佐々木 敦子) was an XIG operator and one of the supporting characters in Ultraman Gaia.

Ultraman Gaia
As a child, Atsuko had a terrible childhood where she was always isolated by the society and found solace in arcade games. She even had once possessed a doll named Lilia which she lost it sometime later.

During her job in XIG, she befriended Georgie, an American worker and operator of XIG. Initially, she had a favor with Kaijo from Team Lightning but quit after he has a relationship with her sister. Atsuko always give Gamu Takayama, XIG's analyser and new recruit a cold shoulder, although she did shows her warming side towards him, to the point where she broke her pen twice when sensing "something wrong" with Gamu while he was at Germany.

Great Decisive Battle! The Super 8 Ultra Brothers
In this film, Atsuko was Gamu's coworker whom supported him in his dreams. After Gamu's battle as Gaia along with Ultras against Black Shadow and their minions were over, Atsuko assissted him in creating Repulsorlift systems and converting a 150 year old ship monument had turned into a spaceship where everyone makes his way to M78.

Trivia

 * Atsuko's personality towards Gamu is best described as Tsundere, meaning a person (commonly an anime character) who is initially cold and even hostile towards another person before gradually showing their warm side over time.