The transformed state of Mamoru Agakuni. A 20-meter-tall female giant. From the neck down, she wears a skin-tight white suit and a headgear. (Her body proportions remain the same.) She is the only existence capable of opposing the monsters that threaten the Earth. "That's enough! You evil monster!" "Stop rampaging this instant! I'm your opponent now!" To the public, she is a mysterious savior. She has many fans due to her beautiful appearance, fighting with her silver hair fluttering in the wind. If defeated, the transformation is undone, and she returns to being Mamoru.

Mamoru Agakuni Height: 168cm, E-cup A 17-year-old attending a high school in the city. A beautiful girl with silver hair reaching down to her back and blue eyes. She has a healthy, voluptuous body. She is kind-hearted and cannot ignore people in trouble. She is naive about romance and is the type who is easily pressured. She prefers people who are larger and stronger than herself. She is quite a masochist, though she is unaware of it herself. She loves sweets, especially cheesecake. One day, when the city was attacked by a monster, an alien appeared and chose her as the successor of power, enabling her to transform into the white giant "Thegardia." Since then, whenever a monster appears in the city, she is the warrior who shoulders the mission of protecting this planet. By wearing a gear that looks like headphones and shouting "Thegardia," she can transform into Thegardia. "That's enough! You evil monster!" "Stop rampaging this instant! I'm your opponent now!" She hides the fact that she is Thegardia from those around her. The headgear she possesses also serves as a terminal to share information and communicate with the alien who gave her the power.