Itsuki was raised in the Bahbem Institute with Makoto Isshiki and Helena Bahbem, and is the adoptive brother of Quon to whom he is very attached to. He is the leading researcher of the RahXephon and Dolems and studies their relationship with music.  He once dated Haruka and is aware of the special connection between her and Ayato. He once tried to pilot the Rahxephon at Makoto's urging only to have the water surrounding it slam him against a wall, taking the form of Reika afterwards. For that he is highly envious of Ayato.

In the year 2012 Japan was invaded by the Mu. Human-like beings from another dimension with blue blood. 
In the year 2015 Tokyo is attacked by invaders, who are repelled by a humanoid weapon called a Dolem. During the chaos, Ayato Kamina meets Reika Mishima, a classmate. 
During that same day, he is attacked by government officials but a woman named Haruka comes to his rescue, informing him that she was sent to get him by the Organization TERRA, and that Tokyo had been sealed in a time rift where time flows one third as fast as the outside world. 
He flees from Haruka onto a train where he sees Reika once more. Arriving at the Room of Rah, he follows her to a tremendous egg where the Dolem RahXephon is hatched from, and upon her singing his mother appears atop the Dolem that had stopped the TERRA Invasion. In the battle Ayato's mother is injured, and Ayato flees Tokyo Jupiter with Haruka upon seeing his mother's blue blood.

Jay Hickman is an American actor, singer and voice actor. He is best known for his prolific voice work on English language dubs of foreign films and television series. Most of these works are in anime that ADV Films has licensed, but he has also voiced numerous Korean and Japanese action and horror films, such as the original Dark Water, released in 2002. Among anime devotees, Hickman has won recent acclaim as Shinichi Mechazawa, the identity-critical robot in Cromartie High School and the emotionally challenged Prince Mytho from the series Princess Tutu.

__Non-Anime Roles:__

- Aestivum Svafrlam Forden - Metaphor: ReFantazio (VG)

Johannes Raspe (born November 29, 1977 in Munich) is a German actor and voice actor.

Ayato Kamina was separated from the girl he loved, Haruka Mishima, when an event occurred that was thought to have killed everyone outside of Tokyo. But one day three years later, invaders suddenly attacked the city. It was then that he meets an agent of TERRA, Haruka Shitow, who tells him that she will give him the truth about the world. It is the beginning of a series of strange events, which involve him activating a giant mecha, the RahXephon and finding out that many people, including his own mother, has blue blood, and that he was actually living in a self-encased dimension where time moves slower than that of the outside world.
 
(Source: Anime News Network)

Quon Kisaragi was surprised when she saw an illusion of herself floating in midair. This other "self" of her claimed that she is a fragment of Quon. Thus an existentialistic dialogue began between the two.
 
(Source: Anime News Network)
 
OVA side story bundled with the RahXephon Special Edition game for the Sony PlayStation 2.

Itsuki Kisaragi