Code Geass: The Miraculous Birthday is a crossover fanfiction between Mobile Suit Gundam 00 and Code Geass: Lelouch of the Rebellion. The storyline is a merge of both series, however the events of Code Geass are more pominent. The story has yet to be posted. In this alternate setting, Lelouch takes Setsuna's role as Gundam Meister under the codename of Zero, with the intention of eradicating war and Britannia.
The events of the story are the same as the beginning of Code Geass, however several changes have been made. The first is during the invasion of Japan, where Lelouch, scrambling through a hellish battlefield, found the warehouse that he, Suzaku, and Nunnally had been hiding out reduced to a pile of ashes. This caused him to believe that the two had perished, and wondered if this was God's way of punishing him for speaking out against his father for not trying to pursue the killer of his wife, however when a Knightmare enters the scene, he believes that no God exists in this world, and that both war and Britannia are to blame for the deaths of his only sister and his first friend. Just before it looked as if he was about to be killed, the Knightmare was destroyed. The events are similar to the holy war of Krugis, as Lelouch, upon seeing the 0 Gundam, thought the Mobile Suit Weapon to be his savior.
Seven years have passed since that event, and now Lelouch, under the codename Zero, is a Gundam Meister of Celestial Being, however unlike the other members, he believes that war will exist so long as Britannia exists, and that the only way to bring an end to war is to destroy Britannia.
Among the changes regarding the story is that the mecha's of the Gundam series are present alongside the Knightmares, called "Mobile Suit Weapons", however because of the difference of capabilities and materials used in their construction, Mobile Suit Weapons are few in number, and the people who pilot them even fewer. Geass is present in the story as well, however Lelouch has been noted to rarely rely on it, in contrast to his anime counterpart.
Formerly known as Lelouch vi Britannia, and under the alias of Alan Spacer at Ashford Academy, he acts as the main protagonist of Code Geass: The Miraculous Birthday, and takes over the role that belongs to Setsuna F. Seiei, piloting the Exia Gundam, and later in R2, the 00 Raiser. While his anime self can keep his emotions under control, Zero hardly ever exerts his, and believes that the world is twisted, much like Setsuna. Ever since witnessing the destruction of the warehouse Nunnally and Suzaku hid out during the invasion, he believed the two had been killed, and blamed it on Britannia and war itself, thinking that neither can be destroyed if one remains. Despite his cold demeanor, he gets along well with Tieria Erde.
The pilot of Gundam Dynames, and Cherudim in R2. The codename is actually given to two people, the first is Neil Dylandy, a victim of terrorist actions that cost him his parents and his sister. He is half-Britannian, like Kallen, and gets along well with her. In R2, the codename of Lockon belongs to Neil's twin brother Lyle Dylandy, and like his brother, he is very cheerful and aloof, however he hates being compared to Neil. He also sympathizes with Zero, knowing what it is like for losing a sister, and tries his best to support him in any way he can.
The pilot of the Kyrios Gundam, and later the Arios in R2. He is known as the "Perfect" Super Soldier due to his incredible capabilities ad skills, due to the genetic enhancements done to his body during his time in the Geass Order. Unlike his anime counterparty in 00, his split personality Hallelujah is actually the result of his Geass, called Absolute Awakening. Because of Hallelujah's violent nature, Allelujah tries his best not to resort to using his Geass, however in certain situations, he is willing to work with him, and as a result, his power is at it's peak. He also despises drugs, specifically Refrain.
The pilot of Gundam Virtue, and later the Seravee in R2. His past has not been explored, however he is dedicated to his mission in completing Aeolia Schenberg's plans to eliminate war from the world. He initially possessed doubts regarding Zero, due to being made a Gundam Meister at the age of 13, however after seeing his hatred aimed at Britannia, and his belief that to eliminate war he had to destroy his country, Tieria began to wonder what brought about his hatred. Since then, he no longer bears any hostility.
The pilot of the Seventh-Generation Knightmare Lancelot, and member of the Camelot Engineer Corps. He is a childhood friend of Zero's, and was believed to have perished until their chance encounter seven years after Britannia's invasion. He is the first to suspect that Alan Spacer might be Lelouch, however when hearing from the boy that the world is twisted, his suspicious begin to dwindle. He also disapproves of Zero's methods regarding his mission to liberate Japan and drive out Britannia, however when learning that he is a member of Celestial Being, he wonders what his true aim is.
Formerly known as Nunnally vi Britannia, she is the younger sister of Zero. As a child, she was very spoiled, but was very naive, and wanted to be with her brother above everything else. During the assassination of her mother, she lost the ability to see and walk, thus leaving her blind and crippled. She was believed to have perished during the invasion of Japan, however she was seen alive and well, attending Ashford Academy as an honor's student. She, like Suzaku, believes that Alan may be her brother Lelouch, despite what others believe. She is also calls him Lelouch in private, though Alan doesn't object. Nunnally is also a supporter of Celestial Being, but wishes they could solve war with words instead of more war.
Originally called Kallen Stadtfeld, she is a member of the resistance cell led by her late brother Naoto, which would soon become later known as the Black Knights. She is the pilot of the first Japanese-designed Knightmare, the Guren Mk-II, and later the Dragoon Gundam, a Mobile Weapon based off the abilities of the Guren, in R2. She, like many Elevens, despises Britannia for taking what they once called home, however it was during an operation to steal poison gas that she encountered the Exia Gundam, and learned of Celestial Being. Shortly afterward, the resistance soon becomes known as the Black Knights, who's goal is to liberate Japan, however Zero states that he plans to take it further. She suspected her classmate Alan of being the masked revolutionary, as he transferred the day after the incident in the Shinjuku ghettos. However, when Zero's identity is revealed, and that he is a member of Celestial Being, she chooses to continue following him with Tamaki and Ohgi.
A mysterious immortal woman that Zero met after he found himself inside the truck that Kallen and another had hijacked, believing C.C. was poison gas. She appears to be aware of Celestial Being's goals, in fact, according to the information provided by Veda, she actually helped found the organization alongside Aeolia Schenberg, choosing his ideals to change the world over Charles'. Similar to the anime and manga, she grants Zero the ability to use Geass, however it is only after Zero states his reasons for joining the organization. She also appears to be an acquiantence of Ribbons, as Alejandro Corner remembers when Ribbons mentioned meeting an interesting girl cursed with the gift of immortality.
An artifical human being, or rather, an Innovator, who was created to help Aeolia's plans come to fruition. He piloted the first known Mobile Suit Weapon, the 0 Gundam, under orders to eliminate all enemies during Japan's invasion. Similar to the anime, he saw how Zero, during his time as Lelouch, admired and stood in awe at the machine, thinking it to be his savior. At some point in time, he encounters C.C., a few years before she was captured by Clovis, and recalled meeting her before shortly after he woke up. It was implied that Ribbons was actually born from the DNA used by Aeolia and C.C., thus making him, in a sense, her child. During the events of R1, he acts as Alejandro's right hand man.
The founder and leader of the private armed organization known as Celestial Being. He was a brilliant scientist, credited for helping in the birth of Knightmare Frames, and also proposed the theory of solar power, which wold soon come to fruition in 2002. Though he was born as a Britannian, he grew to despise conflict, and wished to cease its existence. With the help of an immortal woman named C.C., he created Celestial Being, designed the blueprints for the Gundams, and created the GN Drives, the main component for all Mobile Weapons used in their group. For the sake of its completion, Aeolia even created an artifical being with the DNA provided by himself and C.C., and named the being Ribbons. Aeolia's legacy is extensively researched by Diethard, though the man's reasons are the same for researching Zero after he made his debut in Area 11.