Zero

Zero (ゼロ, Zero) is a public masked identity, originally created and assumed by the former and exiled prince, Lelouch vi Britannia. The mantle was eventually assumed by Suzaku Kururugi following Lelouch's death.

Character Outline
Although for a long time Lelouch remains the person behind the mask, throughout the conflict between Britannia and The Order of the Black Knights, Zero and his distinctive appearance remained a symbol of the anti-Britannian rebellion and the fight for an independent Japan.

Zero's fame quickly spread around the resistance groups throughout Japan. When Lelouch announced The Order of the Black Knights to the world, he remained its undisputed leader as Zero until the Black Rebellion, C.C. sometimes donning the costume to act as a decoy for him. Zero became a symbol in Japan and a messianic figure, even gaining support from Britannia for dealing with unanimously-denounced crimes such as drug trade. However, he became a symbol of controversy following the Battle of Narita, especially after Euphemia li Britannia was accidentally turned by Lelouch's Geass into an enemy of the Japanese and ordered their massacre.

During the first assault on Tokyo, however, Lelouch left the Black Knights behind to seek his kidnapped sister, Nunnally vi Britannia, but was captured by Suzaku Kururugi. In his absence, the Black Rebellion crumbled, and Britannia declared Zero executed to the world. Only a few knew that Zero was alive: Suzaku, Charles, V.V., C.C., Kallen, Shin, Villetta, Rolo and at least six remaining members of the Black Knights.

Although used primarily by one person, a total of three people have assumed Zero's identity throughout the series: the aforementioned Lelouch vi Britannia (as its owner and creator), C.C. (as a decoy and body double at least three different times), and Suzaku Kururugi (as part of the Zero Requiem). Kallen Kōzuki considered donning Zero after Lelouch fell into depression, but seemingly backed off once C.C. warned her of the high burden she had to carry with that mask. Ironically, one of the High Eunuchs briefly confused Kallen as Zero despite her only wearing a towel at the time.

Return
After C.C. restored Lelouch's memories, previously modified by Emperor Charles zi Britannia when he was captured by Suzaku, Lelouch once again assumed the identity of Zero, announcing his return to the world and freeing and reforming The Order of the Black Knights. For a long time, many higher-ups in Area 11 did not believe him to be the same Zero who led the Black Rebellion. For a brief time during Lelouch's depression over Nunnally vi Britannia's plans to recreate the Special Administrative Zone of Japan, Kallen Kozuki considered taking over as Zero, C.C. remarking how metaphorically heavy the mask was.

Lelouch finally returned to his role and came up with a new plan to move some of the Japanese out of Britannian control. Per this plan, Zero negotiated his exile from Britannia in exchange for assembling one million people to participate in the Special Administrative Zone. However, what he actually did was distribute one million Zero costumes among the participants (including the Black Knights), thus making them all fall under the provision. These "Zeros" were evacuated to Penglai Island, which became the new headquarters of the Black Knights, having assumed the function of the United States of Japan's government-in-exile.

Some time prior to the creation of the United Federation of Nations, Zero became the official CEO of the Order of the Black Knights. However, after the Second Assault on Tokyo Settlement, Schneizel el Britannia revealed the truth about Zero's real identity and his use of Geass to the Black Knights, causing them to betray him. Lelouch fled from the Black Knights and Schneizel, rescued by his "brother" Rolo Lamperouge, and abandoned the Zero mask, acting publicly as Emperor Lelouch vi Britannia upon his ascension to the throne one month later. The Black Knights officially hid the truth about Zero's identity and escape, declaring him dead from his injuries in the battle.

Passing the Torch
In three months after Lelouch established himself as Emperor of Britannia, he built up a public image of a tyrannical enemy of the world. It was then that Suzaku Kururugi appeared in the Zero costume and assassinated Lelouch, thus fulfilling their plan for Zero Requiem. Per Lelouch's wish, Suzaku, officially believed to be killed in the assault on Damocles, continued his life as Zero, now considered saviour of the world, unable to show his face. As the second Zero and new leader of the Black Knights, Suzaku remained at Nunnally's side, and Schneizel, previously forced into serving Zero by Lelouch's Geass, turned his loyalty to the new Zero after the Emperor's death.

Policies
Zero (Lelouch) seems to follow the belief of "the ends justifying the means" and is willing to commit evil to destroy another evil. He does not appear to care who knows it, as he publicly declares that belief. Zero is shown to have little concern for innocent lives, shown when he mentions to Kallen about how innocent lives would have to be sacrificed. In the end, Zero states that his primary goal is achieving his own concept of justice and, in doing so, he is willing to do anything to achieve that justice. At first glance, Zero seems to have little concern for the lives of his subordinates. However, this is presumably a ruse as "all are pawns for Zero".

From the beginning, Zero was considered to be Britannia's sworn enemy and was indefinitely branded as a terrorist. Thus, as he killed many Britannian soldiers, this would also lead him to be hated by many Britannian citizens. As the Zero Requiem was completed, everyone in the world, including the people of Britannia, began to cheer for Zero's miraculous return; this later completely changes Zero's image from a symbol of terrorism to a representation of politics and peace.

Costume Design
The Zero costume consists of a tight dark purple suit (changed to a light purple in R2) with golden stripes, long wrapped sleeves, and a frilled white cravat. The outfit combines Victorian fashion with that of a sleek bodysuit; worn over it is a black and gold cloak with crimson spandex lining the inside and an enormous black cape encircling the head. Its immediately recognizable feature is a spiky black and indigo mask with a long variation of the Geass Sigil stretched over its bottom, completely hiding the wearer's face; the mask appears opaque from the outside but is actually transparent from the inside. By unknown means, a small part of the mask can be signaled to slide down, exposing the wearer's left eye; this feature was designed by Lelouch to let him use his Geass without revealing his face.

Nightmare of Nunnally
In this version, the Zero outfit is heavily armored and is manifested from Lelouch's Geass. The mask lacks the four spikes at the edges. He fights at the level of a Knightmare frame as well as any skilled pilots such as Kallen and Suzaku from his armour and cape. The ability of Lelouch's armour functions almost the same as a Knightmare Frame; for instance, his cape can create multiple sharp black whips similar to the Mark Nemo's Blonde Knives. Another ability it possesses is a system called D.O.M. Hostia or the D.O.M. system, which has the ability to control and disable a Knightmare. C.C also fills in as a body double as well. Its also capable of manifesting explosive sigils as well.

Trivia

 * There's a dog wearing Zero's mask among in the one million Zeros.
 * Both Lelouch and Suzaku made their debut as Zero during a staged execution.
 * Additionally,Jeremiah Gottwald has crucial roles on the execute side during the debuts.

Quotes (As Lelouch)

 * "People of Japan and all who are oppressed by the empire of Britannia, long have I waited, all through the struggles against Britannia's injustices, I waited for them to come to their senses, but that hope was betrayed, by an act of barbarism that can only be called genocide. ... Euphemia is the symbol of Britannia's hypocrisy, a murderer cloaked in the flag of a nation. ... I hereby declare our independence from Britannia, but don't take this to mean the resurrection of your fallen nation, we will not turn back the hands of time! The new Japan we go on to build, shall be one broad enough to accept all peoples, histories, and ideologies. Where the strong shall not reign over the weak, and it shall be called The United States of Japan!"
 * "Yes, I am Zero, the man who leads the Black Knights, who challenges the Holy Britannian Empire; The one who holds the entire world in his hand."
 * "People! Fear us, or rally behind us as you see fit. We are the Black Knights. We of the Black Knights stand with all those who have no weapons to wield, regardless of whether they be Elevens, or Britannians. The Japan Liberation Front cowardly took innocent Britannian civilians hostage, and then mercilessly executed them. It was a wanton and meaningless act, therefore they have been punished, just as former Viceroy Clovis was punished for ordering the slaughter of countless unarmed Elevens. We cannot standby and allow such cruelty to be carried out, and so we made him pay for his actions. I will not repudiate battle on a fair and level field, but neither will I tolerate a one-sided massacre of the weak by the strong. The only ones who should kill are those who are prepared to be killed! Wherever oppressors use their power to attack those who are powerless, we shall appear again, no matter how mighty, how formidable our foe may be. Those of you in power, fear us! Those of you without it, rally behind us! We, the Black Knights, shall be the ones who stand in judgement of this world!"
 * "I am Zero! People of Japan, I have returned! Hear me Britannia! All you who have power, heed my words carefully. I am burdened by sorrow. War and discrimination... Malicious deeds carried out by the strong... The same abhorrent interplay of tragedy and comedy... The world has not changed. The people still suffer. That is why the resurrection of Zero was necessary. So long as the strong oppress the weak, my rebellion will continue to grow. It begins today with the divine punishment I have wrought upon the inept and foolish Viceroy Calares. I shall fight against all those who abuse their power. Therefore once again, here and now, I declare the establishment of the United States of Japan! Starting from this moment, this room shall be the first dominion of the USJ! Race, ideology, and religion will not matter. Being a citizen will have but one requirement: to do that which is just!"
 * "What do you do when there is an evil you cannot defeat by just means? Do you stain your hands with evil to destroy evil, or do you remain steadfastly just and righteous even if it means surrendering to evil?"
 * "All of the Zeros! Viceroy Nunnally has ordered you! Now exile from this country at once! No matter where we go, so long as it's in our hearts,we are all Japanese!"