Kabuto said that he couldn't reanimate Jiraiya because his body could not be found as it had sunk deep into the water body.
So the reason why Kabuto didn't revive Jiraiya during the 4th Great Shinobi War was simply because he couldn't find Jiraiya's body. Not that he didn't know where the body was, Kabuto just couldn't get his hands on Jiraiya's corpse. After all, Jiraiya's lifeless body is in the bottom of the ocean right now.
However, their wish didn't see the light of day, as Jiraiya was never reincarnated by Kabuto. 1. Jiraiya - the only guardian besides Iruka that Naruto ever recognized; after he died, it's a great loss not only to Naruto but to Konoha because that's one less protector of the village, and a Sannin at that, too.
How Did Jiraiya "Come Back"? So how does Jiraiya "return" to the series? Well he doesn't quite come back to life in his original body or anything of that nature, but rather, he is given a clone in the form of Kashin Koji of the Kara Organization.
S2 E18: Long Time No See: Jiraiya Returns! While Ebisu trains Naruto on how to walk on water in a hot spring, he spies somebody trying to peep on women in a hot spring.
Jiraiya was fighting against Pain when he was brutally injured and eventually killed by his former student. When he died, his body sank to the bottom of the water inlet outside Amegakure. Kabuto said that he couldn't reanimate Jiraiya because his body could not be found as it had sunk deep into the water body.
Jiraiya loved Tsunade up until the day he died, and she knew that too, but she only realized it when it was too late. Shortly after the Fourth Great Ninja War, Tsunade decided to step down as Hokage, and if Jiraiya had not died, there is a good chance that they would have finally ended up together.
Kashin Koji might not have been born a human, however, he is essentially a reincarnation of Jiraiya. It is in his blood to protect his village, his loved ones, and more importantly, use his life as a shinobi to make a difference to the world, just as Jiraiya once did.
Since Jiraiya was dead, fans never expected for him to return in Boruto, unless via a flashback. However, thanks to the cloning work of Kara's inner named Amado, Jiraiya reappears in Boruto as Koji Kashin who, contrary to early rumors, is not Jiraiya's son.
In the anime, Kabuto simply says that he can't reanimate Jiraiya because his body is at the bottom of the sea. Considering all the other powerful ninja Kabuto brings back, this is a weak excuse, especially since ninja were renowned for properly disposing of comrades' bodies after death.
Kabuto even expressed his dismay over it, stating that retrieving Jiraiya had become impossible due to the depths of the ocean. Jiraiya's body has been resting there ever since, peaceful and undisturbed.
The Second Tsuchikage, Mu — also known as the Null Man — was resurrected by Kabuto during the war. He gave the alliance the hardest time out of all the resurrected Kage. Mu's skills allowed him to perceive chakra across a massive distance, as well as recognize their wielders.
Itachi was reanimated by Kabuto during the Fourth Great Ninja War to fight for him, but he was ultimately able to break through his control and fought against him instead. In an intense fight, Itachi proved to be successful in stopping Kabuto Yakushi, thanks to the usage of the forbidden jutsu, Izanami.
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.
1. Obito never intended to bring back Rin, he only wanted to live on with the sweet memories he had with her. That is the reason he went for Infinite Tsukiyomi where his own dream , a Rin created in his imagination would be reunited with him.
Although Jiraiya ended up dying at the hands of his own student, Nagato Uzumaki, he appears to be back, although as a clone created by Amado using Scientific Ninja Technology. While some are very happy with his return, it has also raised quite a few eyebrows in the fandom already.
Despite some compelling evidence, there are several wrinkles in the theory that Kashin Koji is Jiraiya's son, chiefly, that the Boruto character was never mentioned previously. If Koji uses his father's moves and has history with Konoha, then Jiraiya must've known about his son and trained him personally.
After redeeming himself, Nagato turns back to his childhood dreams. His respect for Jiraiya returns tenfold and he embraces Naruto's ideals of breaking the chain of hatred. He also becomes even more melancholic, contemplating the errors of his ways and going as far as calling himself a "failure".
This is Jiraiya's wife Tsunade. She has supernatural powers and uses “slug sorcery” to battle Orochimaru alongside Jiraiya. At the feet of Sennin is a toad with a skull in its mouth. At the feet of Jiraiya, Tsunade's slug.
With Naruto already noticing Kashin Koji's similarity to Jiraiya, Boruto needs to explore the Seventh Hokage's reaction to seeing a clone of his deceased master, while Kashin Koji must still confront Amado, who cruelly used him as a pawn in the fight against Jigen.
The short answer to whether Tsunade did have any children during her lifetime would be no. There are a lot of theories on why she chose not to have any children. However, as things stand in the current era of Boruto, Tsunade has neither a love interest nor any children to call her own.
Jiraiya. Jiraiya was an exceptionally competent shinobi, and he was the only member of the Legendary Sannin who could actually beat Itachi. He was trained by the Third Hokage, and learned how to use Sage Mode while training with the toads of Mount Myoboku.
The Tale of Naruto Uzumaki. Yes, that has a nice ring to it." These were the final words of Jiraiya and we can see how proud he was of his young protege. Jiraiya's death broke the hearts of every fan that grew up watching him.
The Toad Sages - Following Jiraiya's death, Naruto trains with the toads at Mt. Myōboku in order to become strong enough to defeat Pain. The miniature husband and wife duo of Fukasaku and Shima take responsibility for guiding Naruto, as they did with Jiraiya, and the process is overseen by the Great Toad elder.
If Minato were alive, he would've made sure that Naruto never lacked anything in life, including comfort and a loving parent. Minato would have been Naruto's rock who'd help him become a splendid human being.