Uhh, watching the anime up to 22-nd episode of first series should be enough to know what's going on.
Not sure which genre it fits into, so just left it as "general".
Disclaimer: Don't own Code Geass or any characters
"That's not it, it's just that whenever I give an order, no one can disobey me." Spoke Lelouch. "No matter whether they're commands like 'shoot me' or 'fire Suzaku' they're all the same."
"Seriously, you love playing jokes, don't you?" asked Euphemia.
"It's true, for example, If I were to tell you to 'Destroy the Japanese', no matter whether you accepted or not–" he stopped his speech when he heard his half-sister sobbing.
"I…don't want to kill…" she spoke through tears.
'Could it be that I've become like Mao, who had no control over his geass?' he quickly thought, "Euphie! Forget your previous command!" he shouted.
"I'm sorry Lelouch. I've got to kill the Japanese now." she answered as she quickly fled the room with a gun in hand. He quickly ran after her, but sadly his below average stamina wasn't any good at all, as she was constantly gaining more distance. Near the exit, he saw Suzaku standing next to a kneeling C.C.
"Suzaku, stop her!" he cried out desperately. Normally, the princess' personal knight would not listen to Zero, but the desperation in his voice made him believe the masked individual. He quickly dove at Euphemia, grabbing her hand and forcing her to drop the gun, then pinned her to the ground.
"Suzaku-kun, you're Japanese, are you not? Can you die for me, right now?"
"Zero! Wha–" he began shouting, but was silenced by the harsh tone in Zero's voice.
"I KNOW! I didn't want this to happen!" he angrily answered. He picked the gun up. "Suzaku, maybe your path was the right one, maybe not. But I ask, no, I beg of you, on your knight's honour, to take care of my sister...both of them." He quickly walked to the podium without allowing the young knight to ask anything. He made sure his radio was on – his people were listening, and cleared his throat. Everyone focused on him.
"Everyone that can hear me, listen to me, heed my words! Through a certain ritual, I have gained power that allowed me to force any order on people – the power of absolute obedience. For example, the so called 'Orange' Incident, I ordered Jeremiah Gottwald to make sure we escape and let Suzaku Kururugi go. And now, by an unfortunate accident, I have placed princess Euphemia li Britannia under its influence. Sadly, there are only two ways to stop this ability, one – the order has to be completed, or two – one of the parties has to die. This is why I am right here, right now. I ask of you all, to listen to my final words."
"Dear people of Japan, the Black Knights, my comrades. I ask of you, to place your trust in princess Euphemia, she is someone you can trust, just as I trust her. I have known her for years, and she has kept every one of my secrets, away from friends, away from family, away from anyone and everyone."
He placed the barrel of the gun at his temple.
"Witch, oh dear witch, it seems this poor warlock will be unable to fulfil your contract. For that, I apologize."
His other hand gripped his mask.
"My friends, dear Nunnally…and the rest of the family. I hope you will not remember me as Zero..."
The mask came off, revealing his face.
"…but as Lelouch."
A single gunshot was heard.
So, yeah, just a thought, feel free to use it in your stories or somethin, just mention me I guess, and maybe PM me the link to the story itself :3
Note: I do know that he didn't get Geass through a ritual, but he'd be kind-of a dick to just point at C.C. and say "she gave me superpowers!"
Now, to the people that read my Naruto story – I have not abandoned it, I'm kinda stuck with 'originality' part, because I don't want to simply rewrite the whole canon, neither simply skim through everything that's happening.