Ariel is crown princess of the Invid, an alien race capable of transforming themselves into any form using protoculture. She was sent to spy on a group of rebels but something went wrong and she instead became a rebel herself. Only recently has she accepted her heritage and all of the abilities this affords her.
Ariel is the crown princess of the Invid, a race that live off of a rare plant known as The Flower of Life. Ages ago the Hadonites attempted to destroy the Invid using Neutron-S missiles but were unsuccessful. The Robotech Masters then stole the flower and destroyed most of the Invid home world. The Invid traveled to Earth after the sensor nebula on Haydon V alerted the Invid to its presence there. The Invid conquered Earth and turned it into a slave colony. The Regis arranged for Ariel to be transmuted into human form and inserted into Scott Bernard's group of freedom fighters to act as a spy.
Unfortunately, the Regis did not anticipate the power of human emotions and Ariel did not remember being an Invid. The trauma she felt after her conversion convinced her (as well as the speculation of the group) that she was just some amnesic woman. Scott named her Marlene (after his former Fiance who Ariel reminded him of). She had several encounters with two humanoid Invid, Sera & Corg, who were her brother and sister [Note: Invid are a collective family, however Ariel followed by Sera and Corg are the highest ranking in the collective]. On the journey to Reflex Point Scott and Ariel begin to fall in love, despite Scott's lingering feelings for Marlene Rush.
On the eve of the Battle of Reflex Point Marlene is injured and everyone (Marlene included) is shocked to see her blood is green. She runs away feeling she has betrayed her people, her surrogate family, and the man she loves.
Ariel, upon accepting her reality, acquires many powers that are hers by birth right as a royal invid. Ariel teleports into the hive and tries to convince her mother that what the Invid are doing on Earth is wrong and that she needs to call an end to the hostilities. The arrival of the final attack wave makes a cease fire impossible but the Regis quickly realizes that no matter who wins the battle, the planet will be doomed. She collects all of the protoculture on Earth and collecting all of her children (save Ariel and Sera), departs for another world.