The Legend of Kirito, the Beater, the Black Swordsman

Yuuki smiled as her guild, the Sleeping Knights, and her best friend, Asuna, all cheered happily. They were at the teleport gate way on floor 22. They've just arrived from defeating the most recent boss. The plan was to go to Asuna's log cabin on this floor to celebrate. 

 Yuuki however, just couldn't stop herself from staring at the figure in front of them, Kirito, the Black Swordsman. Now, it felt decent enough to ask him.

"Hey, Kirito, may I ask you a question?" Yuuki asked.

"Hmm?" replied Kirito.

"Privately?"

"Uh, sure."

Kirito was at first puzzled by this rather sudden request, but there wasn't exactly a reason to decline. He turned to his friends.

"Hey, Asuna," Kirito said, "me and Yuuki will catch up with you soon, that good?"

"Sure, just don't be too long." Asuna replied, smiling.

The two swordsmen stepped aside from the group. Some gave curious looks as they passed. Once they were all gone, Kirito sighed tiredly and sat on a nearby bench.

"So, Zekken," said Kirito, "what was it you wanted to ask?"

"Well, I've wanted to ask you to duel with me." Yuuki answered.

Kirito clearly knew that wasn't all it was.

"Didn't we already fight?" he asked, looking rather confused.

"Not really." answered Yuuki, her statement sounding more like an accusation, "You weren't really trying."

"Trying or not, we fought. Besides, you held back yourself."

Yuuki shifted rather uncomfortably. She pointed out that she's seen him fight more than once besides herself. Every time, he looked like he held back.

"I guess that I'm competitive when I like to fight you at your best." Yuuki replied.

"I'm afraid I can't, Yuuki." said Kirito in a sad voice, "Not really sure if I ever will be able to."

"Why?"

Kirito shook his head as stood up from the bench.

"You should...ask the others. Even though it's my story...even the victim isn't the...'best man' to talk about it with." he said.

"I don't understand." replied Yuuki.

Kirito chuckled while looking at Yuuki.

"Funny," he said, "you have that same look in your eyes Asuna had the moment I told her where to find you. I admit that our situation wasn't as unfortunate, but we all have secrets of our own."

And with that, Kirito patted the top of Yuuki's head and walked away, leaving her alone to process what she just heard coming from the Black Swordsman's mouth. 

Most confusing of his words was when he said he wouldn't ever be able to go all-out. She tried to search up Kirito's name on the internet, with an unexpected number of results. That was how she found out his nickname, "The Black Swordsman."  

Even Eugene, general of the Salamanders, had publicly admitted that Kirito was better than him. Anytime Kirito's name was mentioned, it'd be in honor. It was confusing and frustrating to find out what made Kirito so deeply respected. 

Before Yuuki gave up trying to piece everything together, he was heard of playing another VRMMO, Gun Gale Online, aka GGO. 

Within less than an hour of playing the game, he had already beaten an unbeatable gambling mini-game. It was shocking that he could even block bullets. Yuuki herself thought she could block one, but more than that in a row, even with the bullet-prediction lines, it felt impossible to her.