The Fourth Great Ninja War saw the most use of the Reanimation Jutsu, with Kabuto creating an entire army of revived shinobi. The Reanimation Jutsu is arguably the most dangerous technique in the entire Naruto series, offering unfathomable power to the caster, and that too without any sort of side-effects. With this technique, viewers got to see several favorites once more, although a few capable shinobi were missing from this line-up who could’ve surely aided Kabuto in the war efforts.
Shisui Uchiha is one such contender that would have turned the tide of battle in Kabuto’s favor, yet it's quite odd to see this capable shinobi entirely overlooked. While many speculate that it's simply because Shisui fell into the river and his body couldn’t have been recovered, the actual reason lies somewhere else entirely. Looking into the circumstances of Shisui’s death and how the Reanimation Jutsu works can shed some light on this pressing matter.
Shisui’s DNA Could Not Be Found
The excuse of a character’s DNA becoming unobtainable has been used several times during the Great War arc, with the actual reason being something entirely different. Considering Kabuto was able to acquire the DNA of Madara and several other shinobi that had passed away a long time ago, it makes no sense for Shisui’s DNA to be unobtainable. However, in Shisui’s case, this explanation is somewhat plausible given the circumstances under which he lost his life.
It initially seemed that his body was never found after drowning in the river, though it was later revealed that the Uchiha Clan found his deceased body and blamed Itachi for murdering him. However, this doesn’t quite add up as Kabuto would have been able to find Shisui’s body by digging up his grave, similar to countless others. This only leaves one plausible explanation that Obito had something to do with Shisui’s body’s disappearance.
This is backed up by Obito and Kabuto’s conversation, with Kabuto explaining why he revived some shinobi and couldn’t revive others. Kabuto mentions that he couldn’t find Shisui’s body and states his desire for reanimating him, with Obito warning him not to push his luck. The interaction clearly implied that Shisui’s DNA was indeed obtainable, yet Kabuto was barred from getting his hands on it.
Shisui’s Reanimation Would Have Undermined His Death
Several capable shinobi that could have served as useful reanimations yet were excluded from being revived all have a common theme – their deaths were quite compelling and crucial for the plot. Jiraiya was never revived for a similar reason as his reanimation would have undermined his death, in-turn negating Naruto’s character development. Shisui’s case is similar as bringing him back would have made the plot quite complex, though more importantly, it would have surely undermined his death.
Shisui’s death was crucial for pushing Itachi over the edge, leaving him with no other choice but to massacre his entire clan. His death was also one of the driving forces behind Itachi’s motives for protecting the Hidden Leaf at any cost, since it was Shisui’s Will of Fire that had inspired Itachi to serve the village, even if it meant going back on his entire clan.
Reanimating Shisui would have surely created a heart-warming moment between Itachi and Shisui, although nothing substantial would have come about it in terms of moving the plot forward. Therefore, Kishimoto decided to forgo this concept altogether, as it would have simply convoluted an already complicated plotline.
Shisui’s Reanimation Would Have Been Useless
One speculation pertaining to Shisui’s reanimation is that it would have been entirely useless for Kabuto. The Reanimation technique revives the person just as they were right before they died. This can be witnessed in Granny Chiyo and Nagato’s case, as the two were revived in the same state that they had passed away in. Since Nagato died after casting the Gedo Art of Rinne Rebirth, his life force had been entirely drained, a state that was clearly reflected in his revived form.
This indicates that if Shisui had been revived, he would have been completely useless as both of his eyes had been removed before he died. Being an Uchiha, Shisui’s power was entirely rooted in his Sharingan, and without it, he had no special abilities of his own. Being revived in such a state would have simply been a waste for Kabuto.
It is pertinent to note that the Reanimation Jutsu is extremely inconsistent as several plot holes can be witnessed in its application. Madara defies the preset notion of the Reanimation Jutsu as he was revived at a much younger age, although he’s an exception since Kabuto modified his vessel. Itachi had entirely lost his vision before dying, yet he was revived with perfect eyesight, clearly indicating that the Reanimation Jutsu is highly inconsistent. In any case, Shisui being reanimated without his eyes is certainly plausible considering the circumstances of his death, making this theory worth considering as to why he wasn’t reanimated.