I wasn't going to write this story, because I'm a little edgy about writing Nataku (I haven't read nearly enough of X with Nataku in it), but it took hold of me and wouldn't let go. Well, at least it's short. Spoilers: Let's just say, for all of X so far. Beware of metaphors and too-innocent bioroids.

A Game of Chess
By Flamebyrd

"Excuse me. Do you know what..." It fell silent.

"Yes, Nataku?"

"I wanted to know what Good and Evil are, only whenever I begin to ask Daddy a question he just points to the library and won't listen to me."

"Good and Evil are complicated concepts, Nataku." He hesitated. "They're hard to explain."

"I looked in the library," it said, meekly, "but I couldn't find any books on it."

He smiled. "I'm sure there are plenty. But they would all be useless philosophising on the subject. Still, you must have come across it somewhere in something you read..."

It nodded. "They always say that people that kill other people are evil. Am I evil?"

"That depends," he said, slowly, "on why you killed."

"I was told to," it said, promptly.

He laughed, not really amused. "That doesn't make you evil. It makes you a pawn."

"A pawn?"

"Yes. Like in chess."

"Chess?"

He walked over to one of the library shelves and brought down a book on the topic. "It's a game. You play it like this."

Nataku devoured the book in silence. Eventually, it spoke up again, sounding puzzled. "But, I'm not a game piece."

"It's a metaphor, Nataku. It means, if life was a chess tournament, you would be a pawn."

It frowned. "Then who is playing the game?"

He smiled, bitterly. "Many people are playing. Fate is the one that runs the tournament, however, and it decides who wins."

"Who is playing the game I am a pawn in?"

"Now? I rather think it's Fuuma."

Nataku blinked. "Daddy?" It frowned again. "I don't want to be Daddy's pawn."

"You don't like being controlled? You want to have free will?"

"Have I been controlled?" it asked. "What is free will?"

"Free will is when you think for yourself. It's where instead of asking someone what to do next, you think of something to do on your own."

"Oh," said Nataku. It looked at the book, then back up at him. "Are you a pawn, Subaru-san? Which piece are you?"

"I was a player," said Subaru. "I was playing against the Sakurazukamori."

Nataku looked at him, blankly. "But, aren't you...?"

"I lost."

~ END ~

Further Notes:
I realise Japanese people are more likely to play Go than Chess, but Subaru's an educated young lad and I'm just assuming he knows enough about it to make metaphors. Feel free to make an appropriate cultural substitution, however.
And, by the way, English needs a genderless pronoun, for use with beings like Nataku and Kohaku.