Genma had been incredibly embarrassed when he woke up. It was one thing to collapse during training or have a mild emotional breakdown, but both in one day?
Gai-kun and Ebisu-kun had been awake already, and quickly made him stop apologizing for causing a fuss. Chouza-sensei quickly came to get them (Genma figured he noticed the minor fluctuations in their chakra) for breakfast. Their sensei had insisted on carrying Genma, waving away any protests with a request for his student to humor him. Gai-kun had looked so openly relieved that Genma had given in without further comment. He has the sinking feeling that he's heading for a few days of coddling.
While Ebisu-kun and Gai-kun drill taijutsu forms, Genma sits with Chouza-sensei. They go over every jutsu Genma knows, every taijutsu tactic he's familiar with, and every poison he's ever touched. It takes a long time. Sensei's eyes had gone wider and wider the longer he's talked; and he'd outright gone pale at the list of poisons. Which was… fair really. Listing it for Sensei is the first time Genma had really thought about all the dangerous substances he deals with regularly.
It turns out poisons aren't really Sensei's area of expertise. Genma is going to have to sit down with Sensei's Yamanaka friend to go over those. He's not sure how he feels about that, given everybody know the Yamanaka are Konoha's unofficial counselors.
Chouza-sensei lets him off the hook (temporarily) when they break for lunch, and shares some clan history with them. It is a rare privilege, even if nothing they're learning is actual clan secrets. Apparently, the Akimichi had been something like lords even before the Warring Clans era. Their family jutsu is said to have been developed in that time, and the clan had quickly established themselves as a neutral power. The Yamanaka clan had been a small family of neighboring herbalists, and had joined the Akimichi for protection. The Nara had been semi-nomadic deer-herders who pledged themselves to the Akimichi because it was more efficient that trying to maintain their lifestyle with all the fighting going on. The Nara shadow manipulation had first been developed to herd dear, so long ago that it was said no one had ever considered other methods.
Somewhere along the line, the Yamanaka had developed their techniques in an attempt to keep up with their allies. The Akimichi had intimidation and heavy combat thoroughly covered and the Nara could efficiently subdue manipulate opponents from midrange, so the Yamanaka had focused on the remaining aspect: long-range. Their techniques quickly began to go beyond all expectations; useful for scouting, infiltration, interrogation, and combat.
Of course, it hadn't been easy to explore their new abilities; and learning to work together between the clans had been a whole mess. The Akimichi-Nara-Yamanaka alliance had learned quite a bit about medicine as a result.
Genma is always reminded of his mom when Chouza-sensei is teaching them something. There's this thing they do, where they circle around the point until their audience hits it by accident. In this case, Genma knows this is story is directed at him, offered freely in an attempt to trigger reciprocation. Chouza-sensei is very good at it because he seems so jovial and kind. Sensei actually is those things too; but Genma was raised looking underneath the underneath, and the Shiranui are unparalleled experts at hiding deadly things in unassuming packages.
Recognizing that is what convinces Genma to start talking.
The history of the Shiranui starts in the Warring Clans era. They had been a comparatively small family, coming from a village of civilians in the Land of Fire and the fighting was hard on them. The fact that they didn't have kekkei genkai is probably what saved them. Without any distinguishing features or signature moves, they hadn't been hunted as threats. But it also meant that they had less ways to advertise their services. Large, well-known clans could afford to refuse jobs. The Shiranui had survived doing things needed a shinobi's touch, but no well-known clan would do.
But Shiranui adapted, and they became very, very good at doing awful things in ways no one would ever tie back to any shinobi.
When Konohagakure had formed, the Shiranui had joined almost by accident. Hashirama-sama had issued an open invitation to all the neighboring civilian villages.
"It's actually a really funny story." Gai-kun and Ebisu-kun leaned forward in anticipation, "As their civilian neighbors settled into their new homes, the head of the Shiranui family went to the Hokage's office to pledge her family's service. Hashirama-sama – apparently not realizing the woman was a shinobi – asked if they needed any help preparing the fields for planting. Since one does not simply contradict the God of Shinobi, my ancestor continued the discussion along those lines, thanking their Hokage for his offer and leaving."
Genma can't stop himself from smiling widely; remember the faux-innocence on his mother's face whenever she told the next part.
"It wasn't until hours later when Tobirama-sama tracked down the head of the family –demanding to know how she had gotten through security – that Konohagakure realized they had new shinobi."
Genma's mom also used to joke that their family may not have kekkai genkai or any distinguishing features, but you would always be able to identify them by their sense of humor. Not that he is going to bring that up right now. Gai-kun doesn't get the jokes half the time, and Ebisu-kun might concuss himself by facepalming too hard.
Chouza-sensei seems to have come to that conclusion on his own if the look on his face is any indication. Genma is kind of honored their sensei is relaxed enough to genuinely express himself around them. Or at least, Genma will feel honored once sensei stops looking like he's trying not to say 'oh kami, it's genetic' out loud.