A/N: The day. I had. I don't even. Failing to get this chapter out on time is not even the most faily of my failures today. My apologies. Next Friday shouldn't have this problem.

Arrrrrgh.

This chapter's kinda short, for which I apologize. But it contains an explanation on what a half-niece is. Which is kind of worth the chapter on its own.

Thanks for reading, and do please remember to review. Enjoy!

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Of Family Trees

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The Uchiha clan had many rules, regulations, and legal documents.

None of which they shared with outsiders.

Hashirama managed to find a way.

"Madara-sama's too paranoid anyway," Uchiha Hiya grumbled, pulling a large scroll out from a passage hidden by a tatami mat and setting it beside a folded chart. "It's like he thinks somebody wants to massacre the clan or something."

Hashirama said he was sure Madara thought nothing of the sort. Hiya just sighed.

The first thing Hashirama looked at was a genealogy chart of the entire Uchiha clan—which was so immense it took up half the room when unfolded, and looked like a multicolored connect-the-dots mixed with a maze mixed with a spider web. Hiya informed him (with no small amount of clan pride) that it was practically impossible to read it without the Sharingan. Hashirama tried anyway. After several futile minutes of staring at the chart (Hashirama couldn't even find Madara's name), Hiya sighed, relented, and informed him that they had special glasses with colored lenses that could be used to sort out the lines. The glasses were reserved for children and elders who couldn't use the Sharingan, and also, they looked really stupid.

They did look really stupid. Hashirama quietly ignored the fact that Hiya snickered and activated his Sharingan to memorize the sight the moment Hashirama put on his glasses. He took another look at the chart.

There were a half dozen different pairs of glasses, each with different lens colors to highlight different aspects of the chart (who the hell had designed this thing?), and he went through four pairs before he managed to locate Madara. Which was actually kind of stupid, since the names and birthdates themselves were perfectly easy to see; it was just the lines between them that made no sense.

He was shocked and a little embarrassed to discover Madara was seven years younger than him. (Though why should he be embarrassed? It wasn't as though he'd had any inappropriate thoughts about Madara, right?)

He had to switch back to one of the earlier pairs of glasses in order to find the lines stringing out from Madara's name. Two snaking up to Madara's parents, another pair of lines snaking from the parents to another man, younger than Madara, and marked as "deceased": Izuna. So that was Madara's brother's name. Glad to have that confirmed.

(Between Izuna and Madara, there was a tangle of lines; an arrow from Izuna to Madara, an X over Izuna, an O over Madara, a dotted line from Izuna to someone else, a solid line from Madara to that same person with an X in the middle of it and another dotted line branching out of the X and pointing at the first arrow between Madara and Izuna... Very hard to miss. Hashirama wondered what the story here was.)

And then a third line from Madara's father, running parallel to a line from another woman, leading to a woman about sixteen years older than Madara: a half-sister, apparently. And a line snaking from her, running parallel to a line from another man, to a woman who was two years younger than Madara. So that's what a half-niece was. Hashirama wondered what she looked like. He wished he'd paid attention when she'd passed him. (He didn't even remember how long her hair was.)

Besides the genealogy charts, Hashirama looked into the Uchiha marriage laws; that was the scroll Hiya had pulled up for him out of some hidden chamber. For such a big scroll, it had very tiny print. Not a problem for anyone with the Sharingan, Hashirama was sure.

It took quite a while for Hashirama to track down the rules on who could marry whom and why. (In the meantime, however, he learned that in the Uchiha clan, the official mourning period for a loved one was five hundred days; all members of the clan had to have a clan sigil at least the width of their palm displayed on their person above waist height at all times; and it was illegal to be seen outdoors with a folding fan or a pinwheel on Tuesdays, the fourth of the month, or any time in April.)

The Uchiha marriage rules resembled advanced mathematics more than anything else: percentages based on ancestors and blood and how far you had to go back until all your ancestors were the same, and if the percentage was over 46 percent (where had that number come from?) you couldn't marry. (There was no answer to the question of how marriages outside the clan worked; Hashirama was beginning to suspect the answer was "they don't.")

Siblings with the same parents were 100 percent related, since each got 50 percent of their blood from their father and 50 percent from their mother; half-siblings were at least 50 percent related, and a parent and child were at least 50 percent related. Aunts/uncles and nieces/nephews were 40 percent related, and no matter how many times Hashirama did the math in his head he couldn't figure out where they'd gotten that statistic, from the other math he thought it'd be 50 percent related. And did that mean nieces and nephews could marry their uncles and aunts?

And to make everything more worrisome, any Uchiha whose exact relation to another Uchiha was unknown would be given the same percentage as a cousin—which was 10 percent, inexplicably. (So cousins could marry?) But at least that was accompanied by a ban on marriage unless they were reasonably certain the percentages would be low enough. Then again, Hashirama was beginning to wonder what "reasonably certain" meant to an Uchiha.

He finally gave up on trying to figure the rules out and asked Hiya how closely related a person would be to a half-niece. (If half-siblings were half as related as full siblings, then half-nieces/nephews should be half as related as full nieces/nephews. Since full nieces/nephews were 40 percent related, Hashirama thought half-nieces/nephews should be 20 percent. Right?) He was informed it was 15 percent, assuming no other common ancestry.

Hashirama was beginning to get the feeling that the Uchiha clan was fudging with their numbers to make it easier to marry their relatives.

He asked if that meant, then, that Madara and his half-niece were 15 percent related? Hiya seemed surprised by the question, but didn't say anything. He consulted the chart, Sharingan spinning, and informed Hashirama that, no, they weren't 15 percent related. They were 54 percent related.

Whatever the expression was that crossed Hashirama's face, Hiya found it very amusing.

"It's not that strange," Hiya said. "Madara-sama and Izuna-san were 221 percent related."

"How is that...?"

Hiya slowly shook his head. Hashirama decided he didn't want to know.

Hashirama was beginning to figure out why the Uchiha clan had to keep fudging with their numbers to let them marry relatives. Because if they didn't fudge with the numbers, they wouldn't be able to marry at all. They were all relatives.

"Why do you have such elaborate rules?" he asked, as Hiya was putting away the scroll and genealogy chart.

"To prevent incest."

It was only with great difficulty that Hashirama managed to stop himself from laughing in disbelief.

Hiya gave him a withering glare. (With his Sharingan on, it was a glare that made Hiya's relation to Madara very clear; how closely were they related, Hashirama wondered?) "Perhaps it doesn't make sense to someone from a clan where 'family' members aren't even related," he said, "but it's kept the Uchiha clan healthy and powerful for generations. In over a hundred years, less than five Uchiha have made it to adulthood without developing the Sharingan. In that same time, how many Senju have had your kekkei genkai, Hokage-sama?"

Less than five.

Be that as it may, Hashirama still couldn't quite look at the Uchiha clan in the same way after that.

Hiya reminded him multiple times that he'd never seen this stuff, he didn't have this information, he didn't know a thing about the scrolls or the chart or the hidden chamber, much less about anything he'd learned from them, and if someone did find out that Hashirama had seen this stuff, then for the Sage's sake he didn't hear it from Hiya. Hashirama swore that he would take these secrets to his grave. (And he did. The existence of any of the places or items Hashirama had seen was kept completely concealed from the rest of the village, until Itachi informed Danzou about them a few weeks before he massacred the Uchiha clan.)

Hashirama tried to convince himself that Hiya was just too paranoid about getting caught.

He tried to convince himself that he hadn't just knowingly abused his authority, broken into the Uchiha complex, and stolen their clan secrets. All to find out more about a woman and some regulations he didn't even care about, just because Madara had made one little comment in passing. ("She's my half-niece. She's off-limits. To both of us." That was all Madara had said. Why did Hashirama even care, Madara had said she was off-limits to him.)

"Stalking" was not, and is still not, a familiar concept in the Land of Fire.

But even though he didn't know what he was doing, Hashirama still had the decency to feel ashamed of himself.

xxx

It was during that trip that Hashirama finally heard the story about Madara's deceased brother Izuna. He had asked Hiya why he disapproved so much of his clan leader. Hiya had told him.

There was a reason for the odd tangle between Madara and Izuna on the genealogy chart. And for their very high relationship percentage.

They had only been 121 percent related.

Until Madara had taken Izuna's eyes.

Although it wasn't referred to as such, that was the first time Hashirama heard of the Uchiha curse of fratricide.

That. That was the brother Madara loved so much? That was the brother for whom he had mourned so long? He had stolen his eyes? He had doomed him to death?

The next time he met with Mito, some formal meal, and she asked him quietly, eyes shining, what was the latest news, what could he tell her about Madara...?

He told her.

She stared at Hashirama, mouth open, horrified. "That's... that..." She slowly leaned back, slowly squinted her eyes, slowly frowned in concentration, like she was struggling to find an answer that just wasn't there. "That poor man, right...?"

"Yeah." Hashirama nodded in agreement.

"To have to do something like that to his own little brother..."

Hashirama nodded again.

No, of course they weren't horrified at what Madara had done. Yes, of course they pitied him more than Izuna. Everything Madara did was justified, he had his reasons, they understood, they understood.

Poor thing.

It took Hashirama a while to figure out what all this meant.

Madara's eyes, his beautiful, beautiful eyes?

They weren't Madara's eyes. They were Izuna's, Izuna's eyes.

And yet they were so much a part of him...

They held his fire, they held his soul. He spoke with them, he fought with them. Hashirama could see Madara's entire life in his eyes.

Maybe they had not been his originally—but they were now. That was how Hashirama saw it, and how he would always see it.

Nothing would ever change the way he saw Madara.

xxx

The Uchiha clan baffled Hashirama. They had elaborate laws that allowed them to get away with marrying exclusively within their own clan, for the purposes of "preventing incest." Uchiha clan rituals involved stealing one's sibling's eyes. And Madara may or may not have had a thing for long hair.

So the clan baffled him.

That was fine; apparently, he baffled them right back.

He found this out when Uchiha Byakko came to him with a message from Madara, who was doing something out in the western realms of the Land of Fire, some mission which he hadn't told Hashirama a thing about but which Hashirama was happy to assume was very important. Madara's message had gone straight to the Uchiha clan (perhaps one of his hawks had carried it), and so Byakko had taken it to the Hokage Residence.

Byakko often served as the messenger from the Uchiha clan to the Hokage Residence (when Madara didn't operate in that capacity), and sometimes from the Hokage residence to the Hyuuga clan (because the Hyuuga elders respected him as a fellow elder and as a sometimes-ally-sometimes-enemy from previous decades). If the Hyuuga clan had asked Madara if one of their members could marry an Uchiha, they had probably sent the message through Byakko. Hashirama wondered if he should ask whether or not the rumor was true, but figured it probably wouldn't be appropriate and would just make him look silly if it wasn't (and it probably wasn't, he'd heard it from some teen kunoichi).

He shouldn't have worried. When it came to silly questions about silly rumors, Byakko's next one easily beat out any of Hashirama's. (Except for the "does he like long hair" one, that one took the cake.)

"If you'll excuse me, Hokage-sama," Byakko said after delivering Madara's message, "I have a question that I've been puzzling over a while, and I was wondering if you might not be willing to answer it...?"

As eager as he was to read whatever it was that Madara could have possibly sent him, he set aside the rolled paper and gave Byakko his full attention. "I'll do my best to answer, Byakko-san."

"Is it true that you and Tobirama-san aren't related?"

Hashirama stared at Byakko. What in the world. "Why do you say that?"

"That's just what it looks like, Hokage-sama," Byakko said quickly. "I would never have brought it up except... you don't look much alike. It's grown into something of a debate, in my clan—whether or not the Senju clan is an actual family, or more of a... loose coalition of unrelated ninja, more or less."

"Of course we're a family," Hashirama said, then remembered what that probably meant in Uchiha terms and quickly amended, "I mean, when we marry, someone will marry in from outside the clan, and the new spouse joins Senju, but... we're still related."

Byakko nodded slowly, as if the concept of being related to anyone in a clan that didn't exclusively marry with itself baffled him.

Hashirama decided to make it easier for him. "Tobirama and I are fully related, same mother and father," he said, and before he thought it out, added, "One hundred percent." That was a concept an Uchiha would understand. That was also a concept that Hashirama shouldn't have known about, he remembered after the fact. Maybe Byakko would think he'd just been using an idiom and hadn't been explicitly referring to the Uchiha clan rules.

"I see..." Byakko still looked puzzled. "You don't look like you're related. If you'll forgive my saying so."

Well, they weren't 221 percent related, but Hashirama thought they looked related enough. Even if they had completely different hair and eye colors. And skin colors. And facial structures... "Sometimes these things happen," he said, shrugging.

The look Byakko gave him quite clearly said no, they don't. But he bowed graciously and said, "Thank you for your time, Hokage-sama. I apologize for such a bold question."

"Not at all."

And Byakko hurried off to do whatever it was he was supposed to do (report this news to the Uchiha clan, maybe), and Hashirama suddenly wondered—did that mean Madara thought Hashirama and Tobirama weren't related? That stung.

But... Oh well.

It wasn't the worst thing Madara had ever thought about him.

Somehow, Hashirama didn't think he'd convinced Byakko that he and Tobirama were really related. But Hiya hadn't convinced Hashirama that the Uchiha clan's marriage rules were in place to prevent incest, so fair was fair.

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