To study Nature Energy from a broader, more macro-level perspective, Yuhara needed better "mediums" and "vessels."
Research involving danger and taboo was, fundamentally, something Yuhara was doing for his own sake. But its nature could equally be described as "for the better construction of a classical New Konoha"... This was by no means merely a high-sounding excuse. After all, Yuhara had always believed that everyone was better off when everyone improved.
In short, he hoped everyone would become better—but preferably not better than him.
If he wanted to study Senjutsu or Nature Energy more effectively, the best and most necessary test subject was naturally the First Hokage's Cells.
But if he directly requested the First Hokage's Cells from Konoha, there would first be serious ethical problems with such an act. In the hearts of the Konoha Ninja, the God of Shinobi was unquestionably someone who could not be desecrated—at the very least, they could not behave so lawlessly in public. Second, overly powerful forces always made ordinary people wary, which would bring Yuhara unnecessary attention.
The previous example was still fresh in everyone's minds. Yuhara wanted to shape his image as much as possible toward that of a positive researcher, rather than become some kind of mad scientist. Simply put, he did not want to be treated as a second Orochimaru.
Of course, to certain people involved, even the most amicable disguise worn by Orochimaru was still Orochimaru.
Since he would not directly choose the First Hokage's Cells, thereby avoiding becoming connected to Konoha's higher-ups and core secrets because of this matter, Yuhara naturally had another choice... It was a second-best option, but in a certain sense, it was also the perfect choice.
The "fuser" of Hashirama Senju's cells was right before his eyes.
As a survivor of Orochimaru's special