He is also referred to as the Contact, one of the continuous reincarnations of Abel, the sole survivor of the Eldridge crash. Abel was the first being to make contact with the Wave Existence. Fei would be the final incarnation of Abel, for once the Wave Existence was freed, the gene pool returned to normal. He was dropped off in Lahan by Wiseman, whom is also Kahn, his father, and Grahf (they share a similar relationship, as Fei and Id do). After the destruction of Lahan Village, Fei joined with Citan Uzuki and other allies to uncover the web of deception and manipulation surrounding Solaris and, ultimately, System Deus. It is soon learned that Fei has a monster living inside him: himself. Fei is able to (involuntarily) become Id, a very powerful character who is the product of Fei’s pain and anguish at a critically young age.
However, for a brief period of time in Disc 2, the power of "Id" could be harnessed due to the help of one of the three sages of Shevat. System Id allows Fei to build up infinite AP and thus utilize three power moves. He ultimately finishes off Ramsus while under "System Id"; this mode utilizes Nanotechnology by Fei wearing a restraint that would prevent Id from gaining control. After “Old Man Bahl,” another sage, repairs Fei’s Weltall, it becomes Weltall-2.This is the third strongest Gear in the game, second if it is in System Id, since it’s essentially Id in this state. The player is able to use System Id until Fei encounters The Wave Existence. After a final confrontation against Grahf and coming into contact with Zohar, Weltall-2 becomes Xenogears. Fei is a balanced fighter, although his ETH-DEF and ATP are low, and his gear is Weltall, which is destined to become the Xenogears. Fei has the most powerful combos in the game, as well, and decent ATP-up and DFP-up "Chi" spells, along with a few offensive ones.
Fei is a complex character with many issues, which he is able to resolve as his journey continues. One such issue is the being known to him as Id, that resides within him. Fei wants nothing to do with Id, but he still feels responsible whenever Id becomes loose. He later learns from Id himself how he came to be. Once Fei learns to accept things and become one with all of himself, he becomes a powerful warrior with immeasurable combat skill and ability. His love for Elly was small at first, as he sometimes asks why he seemed to know certain things about the Solarian woman he met during his self-imposed exile after destroying Lahan. But after many times in their journey, their combined affection grew until they were able to return to Ignas after finally destroying the Urobolus Gene creature and restoring the gene pool of Ignas’s human population to balance, along with their time together in the Yggdrasil. This love aided them in many of their trails, and no doubt in the end of the game, they will endure no matter what dangers await them. Nothing can separate them, as the case of their previous incarnations, Fei’s love for Elly, and her love for him has existed for ten thousand years (10,000 years) and will continue until the end of the world.