#so....yeah

Hello to the mysterious anon that mentioned me :]

~🐈

My personal HC is that the mokuton is even more rare than doujutsu such as the sharingan, so much so that it only appears once, maybe twice, in a 100 years or so and even then it's no guarantee that the individual will even know they ever had it before they are dead.

By the time Hashirama awakens his mokuton it has essentially become a subject of mythology and speculation, because it's been over two centuries since any Senju was last known to have it.

They don't fully know how it works, what allows one person to awaken it and others not. But one of the few patterns that could be seen thanks to the Senju's very efficient recordkeeping of bloodlines and ancestry was that every Senju who was recorded to have awakened the mokuton was that their parents came from solid and strong bloodlines of Senju with little intermingling of non-Senju shinobi bloodlines. Some thought that the interference of the unique bloodlines of shinobi clans with kekkei genkai or enhanced abilities could affect the probability of a Senju being born with their own clans ancient and rare one.* While not completely accurate, in their defense, they were also not entirely wrong. The mokuton required a very specific set of genes to be present in an individua's DNA, and mostly all of Ashuras descendants carry some of these genes, and this includes both the Senju and Uzumaki though there have been no known mokuton users among the Uzumaki. So occasionally the stars will align and an individual will be born to whom their parents were able to pass down exactly the necessary genes that are needed for the mokuton which provides the affinity for 1. The mokuton 2. Water nature 3. Earth nature. Shinobi (and samurai) already have mutations in their genes which allows them to manipulate chakra the way they do, and clans with kekkei genkai have even more intricate mutations.** Not only would a shinobi who's not a descendant from Ashura not carry the mokuton genes, but if they carried the mutations for a kekkei genkai who knows how that might interfere. To be fair though, they were mostly just bitter that they didn't gain more mokuton users from Hashirama and needed to find something to blame it on and this non-Senju woman who couldn't deliver the goods was an easy target even though she's not at all to blame for it. Hell, there was actually a chance that Hashirama could have passed on every single one of the necessary genes to his kids, allowing them all the affinity for the mokuton.*** But the chance was very very small, and turned out not to be in their favor and thus they only received some from their father and a few from their mother, but still not enough. -----

*also a reason why the Senju rarely have members of shinobi clans with kekkei genkai marry into their own, but are quite inviting to smaller clans with no particular abilities, shinobi with chakra affinity but no clan or name, kekkei genkai and no known ancestry of shinobi, as well as completely regular civilians. They still add new blood, manpower and skills to the clan but without any major risks of bringing the mutations of kekkei genkai into the genepool.

**The kekkei genkai of most clans have been formed through genetic mutations that happened randomly, but in the case of the Uchiha, Senju, Hyuga and Kaguya clans theirs have been present and remained almost unchanged albeit somewhat diluted since the time of their demi-human ancestors.