In the bingo book, there was an entry whose subject defied the law of shinobi as it was known by every shinobi to ever graduate the academy with a decent to half-assed score on their final exam.

The page belonged to a Konoha ANBU with a dog mask. Under the ranking in every bingo book, of course, there were various recommendations on how to deal with the threat. This ranged from the complex, like how to deal with the sharingan they still haven't discovered how he acquired, to the fact that getting out of the way of the fist covered in lightning might not be that shabby of an idea.

But the first and most important was, "When seen with squad, the hound is the priority target." Most ninja would assume that that was because he was the biggest threat and that would be true if the other members of his squad boasted skills that, even if they lacked in pure finesse of their compatriot they certainly made up for in firepower between the short Uchiha and the Mokuton user.

No, the reason he was the priority threat was that, like an actual hound, he would fight tooth and nail to protect his pack, his family. Anyone who managed to land a blow on his teammates would be dead or backing off quickly to avoid the lightning coming at their head at a worrying speed.

He possessed a protectiveness for his teammates that many ninja would have shaken their heads at and sighed at a too emotional ninja had his success rate not been so inhumanly high. As well as the pile of corpses that had dared to harm the ANBU's pack.

The bingo book entry, like so many others was updated as more information came to light, including the shinobi's identity. Eventually he vanished from the ANBU, for a time causing shinobi all over the world to breathe a sigh of relief before he reappeared going solo eliminating targets with an efficiency that was to be envied and feared between the shinobi villages.

And this entry had always piqued the curiosity of one Zabuza Momochi, legendary swordsman of the Hidden Mist. He studied the file and wondered why anyone would protect their teammates with that level of ferocity.

When he watched the ease that the former ANBU dealt with the brothers that he had dispatched to deal with the bridge builder, stopping the two who had dared try to harm his blonde subordinate, he smiled. The brothers had obeyed the bingo book, but failed.

He had no intention of failing when he threw the blade at the oldest shinobi in the small group.

Days later as he lay dying on the bridge he had tried so hard to prevent the construction of, next to his own, horridly under appreciated teammate. He looked up at Kakashi Hatake, Hound of the ANBU, and smiled, because he had done what so many others had failed to do.

He understood.

I only meant for this to be a small tribute to Kakashi, but it wound up as a character study on Zabuza and Kakashi instead. No idea how that happened.