Some parts may seem similar to the introduction for Code Tekka Geass Knight later on
Turn 0: Demon Turn Demon Knight
"Advent Master" Eubulon had been creating another advent key like his own to combat General Xaviax which he dubbed "Zero" for it would be the last thing Xaviax will face; it had the same rider form as his except it had more silver trims and its visor card reader was on the left forearm; he had also duplicated the 2 survive cards of fire and wind that would allow him to change into the survive modes of either Dragon Knight or Wing Knight.
"Excellent, with this I may be able to overpower Xaviax". Eubulon felt good that he will be able to stop his old leader and stopping his plan. "Now, if I can finish with the synchronization of the Rising mode this war will soon be over."
He was experimenting on some new cards in his secret lab, one was the "Rising" card which would allow to combine the 3 forms (which would make him look like Kamen Rider Kuuga in Rising Ultimate form but the belt's symbol would look like the Sam-Taegeuk for balance of the 3 powers) and the "delta fusion" card that would merge the advent beasts he had duplicated for this suit; the Psycorogue, BlackRaider, and Dragranzer into a black and gold color bird the Samjokgo (3-legged bird) , while this was happening, some of the newt monster Minions, the Sheerghosts and their evolved forms Raydragoons stumbled upon and attacked his lab.
"How did they find this place!" as he said to himself while dodging some of the monsters attack, "Never mind" he then got out his Advent key and called out "Kamen Rider", after he transform he attacked them with his sword vent.
While this was happening some of the monsters were destroying some machines for the experiment and it caused an energy feedback and the entire place was getting ready to explode. Eubulon was able to escape before entire place was gone.
"All of that research gone…it would take years to duplicate the process again and those advent beasts were prepared to fight for the greater good too… you may have won this round Xaviax but the war is far from over!."
Little did he know however was that energy feedback had actually sent the Second Advent key, and all of the Advent/mirror monsters in a parallel world of Earth. The mirror monsters were sent to the mirror world of that Earth but seem they couldn't cross over to the real world for some reason, while the advent key had been activated and searching for someone who's near and sensed…
It was all falling apart. Nunnally was gone, the enemy knew who he was, and the Black Knights were being swamped by the sheer multitude of Britannian forces, with no apparent end in sight.
Such were the thoughts of one Lelouch Lamperouge, formerly known as Lelouch vi Britannia, son of Emperor Charles zi Britannia of the Holy Britannian Empire and his fifth wife, Empress Marianne Lamperouge, otherwise known as the Revolutionary Zero, leader of the Black Knights, the so-called champions of justice.
The former prince glared, leveling a handgun at his former childhood friend turned enemy, Suzaku Kururugi, the two of them glaring into each other's eyes, as if daring the other to shoot. He had cornered the former prince in the midst of his escape, shooting off his helmet, revealing his identity to him and Kallen who had also came. Instead of being stunned, it only seemed to infuriate Suzaku, the two of them coming to a standoff, both slowly gauging the best moment to pull the trigger.
The problem was, Lelouch was too stricken to think straight at the moment, his desire to remove the interference and track down his lost sister, Nunnally, conflicting with his unwillingness to shoot his former friend. Suzaku, however, had no such compulsions, especially since he had FINALLY cornered the man that had not only undermined his efforts to improve the system, but had taken his love from him, in an apparently staged massacre.
"Get out of my way, Suzaku." Lelouch warned, his features grim, the exiled prince cursing himself for wasting his Geass on the brown haired teen before him on something as redundant as 'live'.
"Not this time, 'Zero'." Suzaku countered, emphasizing the name of the teen's alter-ego, his features dark as he leveled his own weapon at his friends face "I'm bringing you in for crimes against the Empire."
"The empire is the one that committed crimes!" Lelouch snarled, his other hand waving to the side as he kept his own firearm leveled at Suzaku's head "You keep preaching about changing the system from within, but all that does is let them sink their claws deeper into society!"
"I don't need to explain myself to a TERRORIST." Suzaku stated coldly, his green eyes boring into Lelouch's purple ones, the teen having no reason to fear Lelouch's power of Geass, "Now come quietly, or I'll be forced to shoot."
"You fool!" Lelouch snapped, whipping his handgun at his friends face, only to yell as Suzaku fired first, knocking the weapon from his hand "Damn!" A second shot fired out, this one catching the exiled prince in the shoulder, spinning him around and knocking him to the floor, where he lay grasping his injury, eyes wide. Kallen tried to help but Suzaku reminded her she was just being used and couldn't take it and ran.
"This is Suzaku Kururugi." the honorary Britannian announced, speaking into his mouthpiece as he approached the stricken prince, his features cold and unexpressive "Have subdued Zero, moving in for capture-!"
Red light bathed the area around them, Suzaku looking up in alarm, his eyes wide with shock as an object rocketed towards them, the very air rumbling from the force of it's planet-fall.
'A meteorite?!' the Knight exclaimed, gaping up at it in shock, his eyes flicking to the sprawled form of Lelouch, who seemed to be going into shock from his injury, as he was simply lying there, face up on his back, right at the center of the rock's landing zone.
For a moment, Suzaku gazed at the twitching, gasping form of his onetime best friend. It would have take the briefest of seconds for him to rush to Lelouch's aid, pulling him out of the path. It would takemore to carry him safely out of the blast radius, but Suzaku had undergone military training, and could easily carry TWICE the exiled prince's weight at a sprint. He was actually stepping forward to do it, as murdering Terrorist that he was, Suzaku wouldn't be able to look himself in the mirror if he allowed Lelouch to die like this. Executed for his crimes after being found guilty, maybe, though he'd prefer the prince simply be locked away for life, when the world seemed to black out, as a single word tore through his mind.
'LIVE!'
Automatically, his body moving of its own volition, Suzaku turned his back on his downed friend and ran, full speed, as far away from the blast zone as possible, his thoughts filled solely with the thought, the overwhelming NEED, to survive no matter what the costs. He was still running when the earth seemed to jump, sending him crashing face first into the dirt, just as an explosion tore through the air behind him, dust and shrapnel pelting him from all sides as the shockwave rolled him over. He lay still, as he'd been instructed, his military training rising instantly to mind as he covered his head and waited the blast out, only raising his head from the ground when the noise died down, blinking in confusion as the effect of Lelouch's Geass faded away.
He gaped, eyes widening in horrified disbelief as he gazed down at the crater that had been dug by the impact. Easily fifteen feet deep, and a good 15 feet in diameter, the walls of the crater looked partially melted, testament to how fast it had been going when it ploughed through the atmosphere. At the bottom of the crater, Suzaku's eyes widening in …The was no sign of Lelouch.
"Suz…aku…" a broken voice called out, the Knight jumping in surprise as his headset sparked to life, the voice fixing into that of Cornelia li Britannia, Third princess of the empire, and his commanding officer "Kururugi Suzaku, what is you status? What happened up there? Report!"
"I'm alive, milady." The Honorary Britannian reported, his voice seeming oddly distant as he spoke into the mouthpiece "The explosion was caused by a meteor of some sort…I was caught in the blast radius, but am unharmed."
"A meteor?" the purple haired princess wondered, her voice laced with incredulity, and a hint of intrigue, "what's your status, have you restrained Zero?" Something clattered against Suzaku's feet, the Honorary Britannian looking at object that had brushed against his boot, bending down to pick it up. It was half of Zero's mask, split down the middle from his gunshot, the remainder of the lens had been shattered by the impact, the once flawless obsidian sheen pitted and dented.
"Zero…has been terminated." Suzaku reported, one hand on his mouthpiece, the other holding the remains of Zero's mask up to his face "Repeat, Zero is dead."
Unbeknownst to Suzaku, a third party was witness to the revolutionary's death she had abandoned, Kallen Kozuki looking on in horrified disbelief, her heart shattering as she held the other half of the man's broken helmet in her trembling hands.
What had they not realized was that the Advent Key had chosen him for his mind and Geass making him suitable as a Kamen Rider, although the impact had wiped most of his memories. It had sent him and itself to an Advent Void to heal his wounds and began processing; inheriting Eubulon's vast knowledge, of technology and fighting styles and the mission; to fight the mirror monsters and protect the people.
After being healed the advent key sent him to this world's "mirror world". His old Zero costume changed (to Eubulon's clothes that he had worn when he recalled his armor after being frozen), and facing with some of the mirror monsters that had come along and were nearby.
"Let's Ride", he said and pulled out his advent key, a belt materialized and he called out "Kamen Rider"…
And so begins the battle with Kamen Rider Zero Knight