Rex meets the Seikon no Qwaser gang and must stop a new evil, Rex offers to protect Tomo and Mafuyu from the Adapts; a group that kidnaps nubile maidens for their high quality soma.
Rex Salazar: The hero that Tomo and Mafuyu meet, Rex is a young and strong teenager with the ability to create various machines out of his body at will and take down mutated beings called E.V.O.s. Rex is seen to have a huge crush on Tomo.
Mafuyu Oribe: Is the girl that meets Rex, she is strong and cares deeply of protecting Tomo, She is very skilled in kudo and is will to fight who ever gets in her way. She might have a small crush of Rex from saving her life.
Tomo Yamanobe: Daughter of the St. Mihaiov's last dean and best friend of Mafuyu, she is a sweet, caring, naive and childish, she has the largest bust out of all the main females of the series and is physically weak. She is usually picked on by her peers and has the Qwaser of gold inside her.
Alexander "Sasha" Nikolaevich Hell: The qwaser of Iron as he stalemates and eventually vanquishes the Magnesium Qwaser with such capabilities as forming an enormous black scythe that is at least twice his size along with vibrating the atoms in the iron to generate the immense heat necessary to forge alloys of iron without the need for an external blast furnace. Besides the hostile heretic Qwasers whose neutralization Athos charges him, Alexander is very austere with anyone that decides on her own to refer to him as »Sasha« and has a difficult time adhering to the social mechanics of Japanese society much to Mafuyu's frustration in the early going.
Van Kleiss: Van Kleiss appears to know quite a bit about Rex, and knows what caused the nanite incident. He saw the nanite incident as the dawn of a new age for humanity, and seeks to create a world populated entirely by E.V.O.s. Like Rex, he is able to control his nanites; unlike Rex however, his mutation is unstable and requires a constant supply of fresh nanites, extracted from other E.V.O.s, who are petrified in the process. With his E.V.O. enforcers, the Pack, he has establishes a domain called Abysus at the original site of the nanite explosion, and has seeded nanites for miles in the area. He and The Pack ends up working along the Adepts.
The Adepts: A secret group of thirteen Qwasers who, much like Athos, desire to uncover the Theotokos, though apparently to use its powers for their own ends.
The Pack: A group of E.V.O.s that serve Van Kleiss. The then work along side the Adepts.
Doomsday:A relative to a former member of the nanite project,he is currently hunting down the original members of the project (including Van Kleiss) as revenge for casting out his grandfather ,Eric.
- Agent Six
- Bobo Haha
- Miyuri Tsujidō
- Hana Katsuragi
- Dr. Rebecca Holiday
- Caesar Salazar
Rex gets a new bulid that is called the Rex board that allows Rex to hover which is inspired by the movie Back to the future.