Theiamillis Gre Forthorthe (ティアミリス・グレ・フォルトーゼ Tiamirisu Gure Forutōze), full name Theiamillis Gre Mastir Sagurada von Forthorthe, also known as Theia (ティア Tia) is an alien, the seventh princess of the Holy Galactic Empire Forthorthe and one of the invaders in Koutaro Satomi's apartment.


In the beginning, Theia was arrogant and short tempered. Due to being a princess from the highly advance Galactic Empire Fortorthe, she has a great deal of pride in herself and can't take even the smallest insult (especially when it comes to small body). Most of the time, she would resort to violence to the point of overkill. The only people she respected were her mother Elfalia, her best friend Ruth, and the Blue Knight.

After spending over a half year with Koutaro and the other invaders, Theia began to mature as a person, understanding her previous faults. She became more conscious and respectful of other to the point of worry if could properly lead them. She even showed a more shy and childlike side about herself after falling in love with Koutaro.


The seventh princess of the Fortorthe Galactic Empire and the only child of the current reigning empress, Elfaria. Theia came to Earth and room 106 of the Corona dormitory for her trial to become acknowledged as the next in line for inheriting the throne. Her trial involved owning the land within the specific coordinates generated by the computers in Fortorthe and to earn the allegiance of anyone that ‘owns’ or lives in the location indicated.  Out of the four invaders of room 106, Theia not only needs the room to succeed with her invasion, but she also needs to turn Koutarou into her loyal vassal.

Powers & Abilities

Theia was the strongest in terms of pure firepower from all the resident of room 106. theia can summon any weapon in her Space Battleship storage or just order the battleship to fire from space by using her bracelet.

Later in volume 16 she use her new battle set, Legendary Weapon System series02 "Combat dress" with Accessory "Assault Red". combat dress the design really gives a similar dress sense. The pure white and gold tone color. this combat dress only provide gravity control and booster while the arms is provided by accessory. when assault red selected as accessory additional accessory will appear from black hole and theia turned into wearing a gold and red striped white dress mechanical, shoulders mount double anti-material gun, from the waist to the thigh equipped with a multiple launch missile system, right arm is equipped with rapid beam rifle, his left arm is equipped with recoil-less pile driver. wearing this combat dress provide theia with both firepower(strength) and mobility(speed).