Princess Berryboo is the leader of the Squiddle Friends and heiress to the throne (she will succeed Queen Rainbowberry after she grows up).
Berryboo is shown to be responsible and capable, having saved other Squiddles from tricky situations many times. She doesn't expect gratitude and merely believes that she is fulfilling her responsibilities as a member of the royal family. Without Berry's ability to keep situations under control, it is unlikely the main group would remain stable. Despite this, she is often underappreciated and dismissed as a froufy, spoiled princess or a heartless manipulator.
Berryboo has a tendency to manipulate events to get her own way. Much of the time, when serious danger is posed, this is a good thing, as it gets her friends out of trouble. However, she's very socially adept thanks to her position in society, and she uses her influence and practice to work the system to her own advantage.
It's somewhat difficult for Berryboo to form meaningful relationships due to her social position and her tendency to alienate others by using them for her own purposes, but she has been shown to have some closeness.
The Squiddle Plumthroat has obvious feelings for Berryboo and has been pining for her since the series premiere in 1999, although she has made it quite clear that she's uninterested. Rather than leaving her alone, Plumthroat has persisted in his advances, and discussed with other Squiddles- most notably Creamsicle- how he might win her over. (See Creamsicle's relationship with Berryboo.) Despite his obnoxious persistance, Berry continued to save him from the notorius situations he put himself in, which only furthered his fascination with her. In 5x02, she uninvited him from her party as a courtesy to his ex Soonki, only to have him later rescue her for a change. She was grateful at the time, but as his behaviour didn't wholly change afterwards, she did not reconsider his propositions, and she continued to be completely averse to the idea of tangling with him or anything more.
Creamsicle and Berryboo have a constant rivalry, and perhaps know each other better than any other two Squiddles on the show. Despite their constant pranks on one another, Berryboo has actually never been shown to manipulate Creamsicle. This is highly unusual for her. Additionally, when attempting to woo Berry, Plumthroat approaches Creamsicle, as opposed to someone who might be on better terms with the princess. This suggests there's more to their dynamic than is initially apparent.
SoonkiOnly appearing for two episodes plus a couple of flashbacks, Soonki was a minor character, but still she managed to affect Berryboo's character pretty intensely. In 5x02, Berry uses her social prowess to make Soonki more comfortable at her party, instead of simply serving herself, which is incredibly big for her. Additionally, she discussed her discomfort with Plumbthroat and desire for non-romantic closeness at length with Soonki, despite her aversion to showing vulnerability. Soonki agreed with her about Plumthroat, and the two tangled briefly, before Soonki, who was from a colony of healers, was called back to help with an unspecified emergency which had broken out. Berryboo was temporarily heartbroken but quickly returned to her impervious self, and only Creamsicle noticed that something had changed.