Poi'xa is one of Lady Elementia's nine daughters, gifted with the power of the Poison Element. During Lady Elementia's internal war, Poi'xa was most concerned with her mom's health. So, she volunteered herself to look after Mufog, the dark spirit that was split from Lady Elementia's body, after it was banished to an orbiting rock. Throughout the long years, Mufog's influence slowly created a shadow of Poi'xa's former self until Master Element would challenge the two and save Poi'xa. With Poi'xa grateful for being free of Mufog's influence, she and the other seven daughters created a Life Sphere within Master Element's heart after he was killed by the dark spirit.
Without her "shadow self", Poi'xa is a much nicer girl. She may be poisonous, but she seems to be very friendly and huggable, despite the green sludge that coats her body. She seems to produce the stuff, and can even spit bits of it to hit faraway targets.