Queen Tia

Queen Tia is a member of an organization called Dealers. The FM-ian Virgo (ヴァルゴ, Varugo), along with Corvus, is the most wanted criminal on Planet FM. The two can perform Wave Change to form Queen Virgo (クイーンヴァルゴ), who is capable of using aquatic attacks such as summoning a dragon made of water. She enters the story by posing as a new teacher at Echo Elementary. She is mainly in charge of harvesting Crimson Energy from fallen Noised Wizards. It's later revealed that she used to have a relationship with A.C. Eos while he was a member of the Dealers.

She and her brother were both orphaned in a war sparked over technological advances. Because of this, the two wish to use Meteor G to destroy the world's technology. In order to do that she and her brother enter the Dealers. During that time she was in love with A.C. Eos. However because he left the Dealers, their relationship was dissipated.

At Sheesa Island she and her brother reveal their identities and about Virgo and Corvus. They then escape after Joker destroys Luna.

While Geo is trying to recover Luna, Queen Tia summons a multitude of fake Omega-Xis' to destroy WAZA. She then Wave Changes after she realizes that her plan failed and battles A.C. Eos in his wave form, Acid Ace. When they fight Queen Virgo had the upper hand until Acid Ace uses the last of his strength to punch through her and tries to talk some sense into her, but because of Virgo's influence it fails. She then battles Geo and was subsequently defeated. At this point he reveals his past about him and Queen Tia.

When Geo, Sonia and A.C. Eos approach Mister King, Queen Tia and Jack then appears and Mr. King reveal his plan, then Acid Ace and Grave Joker battle each other and both disappear. Before that, he finally reveals that he still loves Queen Tia.

Because of A.C. Eos "death", Queen Tia's heart was shattered and she demanded to use Meteor G to destroy the world. As Queen Virgo, she and Jack Corvus confront Mister King but because of the waveout ring, they were trapped. Heartless then reveals her true identities as a WAZA spy (not truly confirmed at that point in the story) and trapped Mr. King instead.

Queen Virgo then went into Meteor G herself and was defeated once more by Geo. With the help of Jack they finally talk her out of revenge. Virgo, who was scared of imprisonment decided to turn on her, resulting in only Virgo to be deleted by Rogue. After that they leave Meteor G.

After Meteor G had been destroyed it was revealed that A.C. Eos was not in fact, dead. Queen Tia and A.C. Eos are finally reunited again after a long time.

Trivia

 * Queen Tia bears a strong resemblance with Pandora both making use of the water/ice elemental, but being of rather cold and quiet personalities, the two also having a male sibling of aggressive personality and the two of them serve a "king". Queen serving Mr. King while Pandora serves Albert who calls himself a king.
 * Strangely enough, her role in MegaMan Star Force 3 strongly resembles Shuko Kido from MegaMan Battle Network series. Being the two are older than the protagonist, has unpleasant past life, has little brothers (although Queen Tia only has one), work as a teacher (although Shuko only start to do so in MegaMan Battle Network 6, and has water element. The major difference is that although Shuko has bad luck and often puttering, she's still kind to anyone, and she's never blame others or do something impulsive as a comeback. Queen Tia however, has a deep grudge towards all that happened to her and her brother, thus turn her to be a cold person and decide to take revenge. Shortly, their personality are backwards: Shuko is as calm and clean as a flowing water, while Queen Tia is as rough and unforgiving as the deep sea.