[Pink-chan]

There are two images in Mutuality, "Suzaku X C.C." and "Lelouch X Suzaku" from Mutuality which came with two short stories by Okouchi. They are by Suzaku and Lelouch's POV respectively in sequence. The setting of the stories was during the one blank month when the three of them, Lelouch, Suzaku and C.C. were together before Lelouch ascended the throne. Since it's by Okouchi, there is some validity for this to consider as canon I suppose.

Here is the summary by Ms Blottyparchment on the story by Suzaku's POV

Spoiler for Story 1: Suzaku's POV:

Lelouch, Suzaku, and C.C. are inside a cafe. C.C.'s sitting on the counter, eating pizza as usual. C.C. makes small talk with Suzaku, asking him if he knew the meaning behind the name of the town. Suzaku says he doesn't, but C.C. will tell him right? C.C. acknowledges Suzaku as a kindred soul and explains that in Persian, the name of the town means God's gift.

Meanwhile, Lelouch is staring intently at a chessboard while fingering a black king in his hand. He is trying to find a way to defeat the white king. Suzaku approaches him. Lelouch keeps his eyes on the chessboard as he tells Suzaku that they cannot go back to the past anymore. Then, Lelouch tears his eyes away from the board and says, "Nunnally's gone." Suzaku is reminded of the figure of the ten-year old boy in the Kururugi Shrine. The stubborn young prince.

They played a lot, listened to the radio, sang songs, smiled, touched...Those days were fun and full of kindness. C.C. chinks her glass to remind them that she is still there. Suzaku knows that they not only lost some things but they also have to carry burdens (responsibilities, sins).

"Lelouch, you who have the power of geass today, you have been more gifted with wisdom and intelligence since before. You also live a burdened life." Lelouch looks at Suzaku and Suzaku sees himself reflected in the former's eyes. They took away so many lives. While wanting to save and help others, they took away many lives.

"To live, that is to grasp for tomorrow. (lit. 'Life, that is tomorrow.)"
"That's right, Lelouch. We snatched away many people's tomorrows. That is why..."

Lelouch touches his right hand to his left elbow and Suzaku understands this signal to mean, "I understand."

Lelouch closes his eyes. Suzaku wonders who he is remembering. Nunnally, who was engulfed by the light of Freya? The parents he punished by his own hands? Shirley? Euphie? Or his brother...?

"Ah, that's right, Suzaku," Lelouch says in a soft voice. Ka-shin~Lelouch places his black king on the chessboard, resounding with determination.

"Zero Requiem...that will be the name of the final chapter."

I gave a shot in translating and summarising the short story in the book from the language I understand on the part on Lelouch's POV (Lelouch & Suzaku image). Pardon me for the bad translation. For those who is able to understand, please correct me if there is any mistake.

Spoiler for Story 2: Lelouch's POV:

Zero Requiem.
Suzaku just stared at Lelouch a little as he spoke to him on the details. He nodded his head most probably with some resolution concerning Lelouch's and his own fate.

The story started with Lelouch changing into his new emperor attire. He was musing how befitting this attire is for the last emperor of Britannia who is going to leave the name of the “most evil” in the history. It will match with the blood which is going to cover on this brand new of white. Next, there is this specially made ‘The King's Sword” which the design also matches the attire of death.

Lelouch walked to his throne with the sword where Suzaku was waiting in his attire of the 'white knight' (this refer to what he was wearing in the artwork above).

Knight of Zero… who would have known that this is a pun to Suzaku who would become ZERO one day.

To allow Suzaku to see the sword clearly, he unsheathe the sword. The body of the sword sparkles bringing an aura of coldness.

“What do you think? Suzaku.”

To Lelouch, what he wanted to hear, to be specific, “Can this sword kills me?" But there is no more words needed between them.

Suzaku said nothing. He kneeled down and touches the sword.

“Suzaku, I'm the emperor, you are the knight. This is just formalities, there is no need to kneel down to me.”

“I bend on my knees, not because you are the emperor, this is my respect to your resolution.” Suzaku answered.

Lelouch realised that he was right to have chosen Suzaku as the new ZERO, who would be responsible for killing him.

“Suzaku, can you kill me?”

“Yes, I will use this sword to kill you and myself at the same time.”

“That’s right. Lelouch Vi Britannia and Kururugi Suzaku will disappear from this world on the same time. Our existence is not allowed.

Suzaku questioned Lelouch if there is no other way.

"NO!" Lelouch answered immediately.

Lelouch admitted there may be other ways. There are many other ways for the case in removing Schneizel and other obstacles but that was the only way for Lelouch. Mind/heart and reasoning are two different issues, he won’t consider other methods.

Lelouch returned the sword to its sheath and handed it to Suzaku.

“I’m counting on you, Suzaku!” Suzaku took the sword and accepted it.

“Yes, Your Majesty！”

That was the hateful phrase used to show respect as a formality to distinguish between the emperor and his official. However, this "Yes, Your Majesty" had a different meaning to them.

"Don’t forget our promise. You must kill me and make it up by living on. Confirm the sin and the punishment. This is our pledge."

“Let’s go, Lelouch. C.C. is waiting.”

“Let her wait, men need some time to change his clothes.”

As a response to Lelouch's joke, Suzaku chuckled.

“You are a person who will not settle down without folding the clothes you removed since before.”

“That was just an unconscious habit from folding Nunnally’s clothes.”

“That’s just like you to use Nunnally as an excuse.”

“That is better than being boorish.”

The boys left the throne teasing each other.

It’s ok, we are still laughing. The changes had already occurred. Knowing each other is real and it is vivid.

That’s why Suzaku can do it.

Because, he is who I acknowledged as my only friend.

That was the promise they had . Suzaku attempted to get Lelouch to find some other ways but was rejected. Lelouch was stubborn, aren't he? Suzaku had respect to Lelouch for his decision. Both of them really wanted to punish themselves. Is there a need for that? They had already chosen this very path, there was no turning back. The last part of them teasing one another is really sweet. They seems like they had returned to before when they were in Kururugi Shrine even though they can no longer returned to what it was before (refer to the story on Suzaku's POV).