When Ester first met Ben in Hot Stretch, they fought for a nuclear device. Later when she realized her kind were doing evil things using the device, she defected to Ben's Team. She brought him to her friends' town, and they played hockey. Ben turned into Water Hazard and splashed everyone with water to cool them down, including Ester, despite her unwillingness. He then brought her a towel, and she blushed as he gazed at her. She turned the water floating around him into snowflakes and ran laughing. Rook told Ben that she liked him. Later when her kind realized she was now the chief, she hugged Ben and told him she and her kind would be good neighbors.
At the end of Hot Stretch, Ester's friends called Ben her boyfriend, and Ben at first denied it, but then excitedly asked Rook if he had a chance with her.
In Rules of Engagement, Ben decides to help Ester rebuild her ruined village at the end of the episode and Ester gleefully agrees, remarking her own love of Mr. Smoothy, hugging Ben close.
It's also mentioned in Return to Forever that Ben and Ester went on a movie date at some point, which Jimmy Jones blogged about. According to Ben, it was one movie, and no food.
While nothing committed between them, Ester has shown to be very possessive of Ben, refusing to let either Looma or Attea take Ben as a husband. Also, Ester showed noticeable jealousy towards Kai Green, seeing that Kai and Ben had history together. She was later horrified when Spanner reveals that Ben and Kai end up together in the future he comes from. By the end of the episode, however, Ester appears to have gotten over that fact not letting it bother her, even forging a friendly bond with Kai. Though it's highly likely she still has feelings for Ben as he does for her.
In The Most Dangerous Game Show, deciding not to fight fate now that she knew of Ben's future with Kai, Ester decided to end her relationship with Ben on good terms even stating she still likes him, moving on to date Antonio.
Like the rest of her kind, Ester is able to stretch her limbs to incredible distances.
Ester is shown to be agile and to possess considerable strength. She is also proficient in hand-to-hand combat, able to fight en par with Rook.
Weakness: Due to her elastic nature, Ester can be tied up with her own limbs, leaving her incapacitated for quite some time before freeing herself.
Like the rest of her kind, Ester has a harder time dealing with cooler climates. However, due to her half-breed nature, Ester is able to handle such conditions far better than a full Kraaho, feeling only slightly chilly in +100 °F temperature.
- Ester's voice actor Tara Platt and Ben's voice actor Yuri Lowenthal are married in real life.
- According to herself in Rules of Engagement, Ester is fond of Mr. Smoothy's.
- Ester was designed by Shakeh Hagnazarian.