Gratcia is a supposedly false Toa who joined the SpiritBreakers while she was an undead Matoran. The (false?)Toa transformation seemed to have an effect on her attitude as well.
She was once Peku's sister, a purple and pink Matoran who could do nothing but worry about her brother. When she was captured by Wons Titel as ransom for an Artifact the evil Makusi wanted, she could not help but worry for her kin.
When they both escaped later, they split back up with Peku being captured and Gratcia serving in Bob's mercenaries, a band of friends who seek money for their services as fighters.
She was later found to have the plague, and was crazed soon after bringing the legendary Artifact to Wons. She died not long afterword and was then put to service under the Brotherhood of Ak'Rei'An's undead-controlling powers.
When the BoA's base called BlackWave was attacked, the powers of the Brotherhood were greatly weakened, allowing Gratcia and five other Matoran, including Carlos to escape their clutches.
She then vowed to get revenge with the BoA and served as a spy squad leader in the New Order of the SpiritBreakers. When she was in the then-new base of Fu-Suva, Peku put on a seemingly normal Kanohi Komau turning them both into what appeared to be Toa.
She has since struck up a relationship with Blur, an old member of Bob's mercenaries. During this period, her attitude also seemed to have changed alowing for arrogance and haughtiness.
Conleroth recently told them that judging by the Komau Peku still wears, they could both be false Toa made to serve the Xiliks.
Gratcia's mask power and elemental power were both unknown until a recent trip to Ga-Terros. When on the shore of Terros-Nui she encountered and fought several Hoi Turtles. During these confrontation she discovered that she was full of elemental energy. Her mask allowed her to switch between elements, though she has only mastered Fire, Air, and Ice.
Sister of Peku. Granddaughter of Old Peku.