In the original story, Dan Katō's death was most likely due to his physical body's hiding place being discovered, or his teammates failing to protect it properly.
However, it was also possible that Dan Katō had been dragged into battle before he had the chance to use the Spirit Transformation Technique, leaving him gravely wounded and beyond saving.
But the Spirit Transformation Technique's sole weakness simply did not exist for Uchiha Gen, because he possessed the Soul-Soul Fruit's power!
By conventional means, he could have Homies like Zhurong and Wusheng guard his body. He could even temporarily create a Homie territory.
Within Homie territory, enemies would find it difficult to locate his physical body. Even if they found it, reaching it would be difficult, since the Homies could move his body elsewhere.
Even if the enemy was so powerful that numerous Homies could not stand against them, they could still stall long enough for his soul to return to his body.
The best approach was to use the Soul-Soul Fruit's soul-splitting ability. Part of his soul could leave his body through spiritual transformation, while another part controlled the body. That would eliminate all the risks!
Since the original Dan Katō had long since died and no longer had a physical body, he could freely traverse the battlefield. The living could not do the same.
However, Uchiha Gen's soul was far stronger than an ordinary ninja's. The distance he could travel was not something the living Dan Katō could compare to.
Furthermore, thanks to his soul-splitting ability, there was no time limit at all. He could remain outside his body for as long as he wished!
And because of that same ability, Uchiha Gen could attack multiple people at once, unlike Dan Katō, who could only attack a single target.
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