Devil_Hex
Dojitsus such as the Sharingan appear through the surge of a specific chakra as explained in the anime. It's like mutating their eyes, then wouldn't Fujin be able to somehow acquire/develope one when he develops his medical and Healing ninjutsu knowledge so he could experiment in this field. Maybe with the help of Jashin's unique Fuinjutsu that grants abilities this could be possible in the future. He doesn't have to necessarily get dojitsus that are inherited from the Otsutsuki.
Your favourite commenter is back and this time with another joke, but before that I am gonna promote two stories that I have read and want more chapters of and what is the better way other than making people aware of it.... so I shamelessly announce the stories which I came across :- "Pokemon- The timeless Journey" and "Naruto: Shadows of Perfection", The former is created by a reader of this fiction itself and I have even seen DevilHex in the comment section... the latter is by the author who have create few stories "My Researching journey(HxH)" and "One piece :Limitlessness", those two were amazing, you might check those out. The joke or more like fax:-
Get the eyes for a possible future ritual as a sacrifice and kill him, if both don't know how raiga ended up like that then defending yourself from it is close to impossible and is a risk that should not be taken Don't know why you added the passive kotoamatsukami, i remember Reading in most fic that he just had a better byakugan that could listen on everything in his range and could hear people's thoughts, could also see and transfer life force, and the capacity to hide chakra and make illusions with his dust, one of the most OP dojutsu honestly in a fic where the mc doesn't care about keeping his own eyes and want upgrade they're the best available