Dan Kato in Naruto

After experiencing the tragic loss of his younger sister, Dan Kato became passionate about the importance of having medical ninja assigned to every squad. His belief resonated with Tsunade, who shared the same conviction. The two of them found solace in their shared vision and grew close, eventually entering into a romantic relationship.

During their time together, Dan confided in Tsunade his dream of becoming Hokage. He longed for the title to protect the villagers of Konoha and ensure their safety. Tsunade, in a heartfelt gesture of support and encouragement, bestowed upon Dan her grandfather's necklace as a symbol of good luck and a reminder to pursue his dream relentlessly.

Dan's commitment to his village led him to participate in the Second Shinobi World War. During the intense conflict, he showcased his formidable skills by employing the Spirit Transformation Technique, a unique ability that allowed him to become a living spirit to engage and defeat numerous enemy shinobi.

Tragically, Dan sustained mortal injuries in a fierce battle. Although Tsunade, who possessed remarkable medical expertise, managed to staunch the bleeding, the severity of his blood loss proved insurmountable. Despite her best efforts, Dan succumbed to his wounds, leaving a profound impact on Tsunade and those who knew him.

In the aftermath of Dan's passing, Tsunade took his niece, Shizune, under her wing and became her mentor. However, the loss of Dan, coupled with the weight of the war, eventually took its toll on Tsunade. She made the difficult decision to depart from the village and retire from the life of a shinobi, seeking solace and a new purpose elsewhere.

After Dan's tragic demise due to severe blood loss, Tsunade was deeply affected by the experience, leading to the development of hæmophobia, a fear of blood. This phobia rendered her unable to actively participate in subsequent battles, and she eventually decided to leave Konoha, accompanied by Dan's niece, Shizune.

Tsunade's departure from the village allowed her to cope with her loss and find solace outside the realm of constant conflict. Years later, Orochimaru, a former ally turned rogue, approached Tsunade with an offer to bring Dan and her brother Nawaki back to life. However, this revival would require the sacrifice of two living beings.

Despite the temptation and her enduring love for Dan, Tsunade made the difficult decision to decline Orochimaru's offer. She believed that Dan and Nawaki would not want her to exchange two innocent lives for their own. Tsunade's choice demonstrated her strong moral compass and her unwavering commitment to preserving life.

Throughout the years, Tsunade remained steadfast in her love for Dan. She continued to reject the advances of her long-time comrade, Jiraiya and refrained from engaging in romantic relationships with other men. Tsunade's loyalty to Dan and her enduring affection for him served as a constant reminder of their deep bond and the love they shared.

Fourth Shinobi World War: Confrontation

In preparation for the Fourth Shinobi World War, the cunning and manipulative Kabuto Yakushi utilized his forbidden technique to reincarnate the deceased shinobi as his own personal army. Among the resurrected was Dan Kato, brought back to life with the purpose of fighting against the Allied Shinobi Forces.

Reanimated and mobilized alongside fellow resurrected shinobi Asuma Sarutobi and Hizashi Hyūga, Dan found himself on the Land of Lightning's coast. Emerging from the depths of the sea, he appeared amidst the ranks of the White Zetsu Army, ready to face the opposing First Division of the Allied Shinobi Forces.

It was during this time that he encountered Chōza Akimichi, a fellow shinobi whom he had crossed paths with in the past. As the conflict unfolded, Dan took the opportunity to explain his unique abilities to the opposing shinobi. He revealed that in order to activate his Spirit Transformation Technique, he needed to be captured and contained within a barrier.

Despite the efforts of the shinobi to subdue him, Dan expressed his admiration for their perseverance and resilience while trapped inside the barrier. However, the tide of battle shifted dramatically when the monstrous Demonic Statue of the Outer Path unleashed a devastating attack.

The force of the assault destroyed the barrier that held Dan captive, freeing him from confinement but causing significant injuries in the process. Although wounded, Dan's undying spirit drove him to continue fighting. By the following day, he found himself once again sealed within a barrier, unable to escape its confines.

From within his temporary prison, Dan observed the arrival of Naruto Uzumaki's shadow clone on the battlefield. Mistaking Naruto for Nawaki due to their striking resemblance, Dan's curiosity was piqued. Learning of Tsunade's trust in Naruto and his unwavering promise to become Hokage without succumbing to death, Dan sought answers about the young shinobi.

Shikamaru Nara, a trusted ally, informed him that Naruto was the jinchūriki of the Nine-Tailed Demon Fox and had always carried the dream of becoming Hokage in his heart. In that moment, Dan experienced a profound realization—both his own dream and that of his brother, Nawaki, were living on through Naruto.

Fourth Shinobi World War: Climax

Continuing his conversation with Chōza while being guarded within the barrier, Dan was overwhelmed by the news of Madara's reincarnation. However, what shocked him, even more, was the revelation that Tsunade had become the Hokage and had joined the other Kage in the battle. Despite Chōza's reassurance, Dan firmly believed that underestimating Madara would be a grave mistake.

In his conviction, he expressed his belief that the only person capable of defeating Madara was someone who had already passed away. With urgency, Dan implored Chōza to shift his focus towards locating and stopping the individual responsible for resurrecting Madara, as he saw it as the only way to overcome their formidable adversary. In his heart, Dan silently pleaded for Tsunade's survival, aware of the immense danger she faced.

As the Impure World Reincarnation was dispelled, a radiant light engulfed Dan, causing him to undergo a process of deconstruction. Amidst the dissolution of his form, he expressed admiration for the person who had halted the technique, recognizing the significance of their actions. Freed from the control of the reanimation, Dan beseeched Chōza to remove the barrier that had restrained him, allowing his spirit to ascend freely.

Grateful for Chōza's understanding and cooperation, Dan enacted his Spirit Transformation Technique, seizing control of his ascending spirit. With a profound sense of purpose, he swiftly made his way toward Tsunade, arriving just in time to intercept one of Madara's attacks and shield her from harm. Engaging in a conversation within the depths of Tsunade's subconscious, he expressed gratitude for her accomplishments, acknowledging that she had achieved what he had been unable to in his lifetime.

Deeply remorseful for the hardships he had caused her, he apologized sincerely. In a heartfelt exchange, Dan assured Tsunade that he would be waiting for her in the afterlife, but he urged her not to follow him just yet, as she embodied his dream itself. Planting a gentle kiss on her forehead, he conveyed his profound gratitude for being given the opportunity to be reincarnated, enabling him to fulfill his ultimate purpose of protecting her.

As a final act, he seemingly infused the remainder of his chakra into Tsunade, rejuvenating her Strength of a Hundred Seal. With his mission accomplished, Dan's soul peacefully returned to the realm of the afterlife,

Dan was an exceptional individual who held an immense love for his village and its inhabitants. His devotion extended to his sister, whom he would often fetch from the Academy—a tradition he continued with his niece later on. Renowned for his wisdom and unwavering sense of honor, Dan wholeheartedly believed in the pursuit of justice.

His profound knowledge of the shinobi world's history made him acutely aware of the implications when he discovered that Madara Uchiha had been resurrected. Dan approached this revelation with caution and wariness. Even upon learning that the five Kage were engaged in a battle against Madara, he harbored doubts about their chances of success.

His primary concern was to prevent Madara from inflicting further harm, hoping fervently for the cessation of the Impure World Reincarnation before it allowed Madara to claim more lives.

Dan had long, pale blue hair that flowed down his back and dark green eyes. In his original form, he wore the standard Konoha shinobi attire with a forehead protector and a pocket-less flak jacket. After being reincarnated by Kabuto Yakushi, his eyes gained black sclerae, adding an eerie touch to his appearance.

Dan was widely regarded as a highly capable and efficient ninja who served his village with great skill and dedication. While limited information is available about his abilities, various indicators suggest that he possessed exceptional talent and prowess on the battlefield. This was evident when Kabuto Yakushi chose to reincarnate him, recognizing Dan as a valuable asset in the ongoing war.

His chakra control was particularly noteworthy, as he demonstrated the ability to transfer chakra at will. This showcased his exceptional levels of chakra control and reserves. In a remarkable display of his abilities, Dan even restored Tsunade's depleted chakra reserves and revitalized her Strength of a Hundred Seal before departing to the afterlife. This showcased both his proficiency in chakra manipulation and his immense reserves.

In addition to his chakra prowess, Dan showcased remarkable physical abilities. In the anime, he exhibited exceptional taijutsu skills, displaying impressive speed, agility, and evasive maneuvers. He showcased his prowess by single-handedly disarming and defeating multiple enemies, emphasizing his proficiency in close-quarters combat.

Dan possessed a unique and formidable technique known as the Spirit Transformation Technique. With this technique, he could transform into a living spirit, enabling him to attack opponents in a spectral form. Furthermore, he had the ability to take control of a target's body using this technique.

Dan mentioned that this technique claimed many lives during his lifetime, highlighting its deadly nature. He specifically requested his opponents to trap him within a barrier before he could activate the technique, indicating the need for caution when dealing with his formidable abilities.

Chōza acknowledged the challenge of trapping someone of Dan's caliber, emphasizing the difficulty in containing his power. In terms of elemental abilities, Dan exhibited proficiency in multiple nature transformations. He displayed competence in Wind, Fire, Earth, Yin, and Yang Release, further showcasing his versatility and expertise in manipulating various elemental forces.

• (To Tsunade) "It is because we are living in the shinobi world, where death is always following us, that I… want to put my life on the line to subdue this war-ridden world. I dearly love both the village and my comrades… That is why I want to protect them." (To Tsunade) "For the sake of everyone's safety... Being Hokage is my dream..."

• (Last words) "I...can't...die...here..."

• (To Tsunade) "Thank you, Tsunade… You accomplished more than enough of the things I wanted to do. …I'm sorry I make you feel nothing but painful emotions. I will wait for you on the other side. But please take your time in going there. Because you are my dreams in the flesh. I was able to protect you at the very end… Maybe being brought back by Impure World Reincarnation was worth it…"

• Dan's name is likely a reference to the historical ninja Kato Danzō, known during the Sengoku period of Japan.

• His family name, "Kato," translates to "increasing wisteria."

• Dan made a cameo appearance in the ending omake of Naruto Shippūden episode 129, alongside other deceased characters.

• According to the databook, Dan completed a total of 574 official missions: 77 D-rank, 84 C-rank, 223 B-rank, 168 A-rank, and 22 S-rank.

• His favorite word was "Peace" (平和, Heiwa), shared with Itachi Uchiha.

• The fourth databook listed Hiden among Dan's special characteristics, although none of his techniques are classified as such.

• Dan's ability to project his soul outside his body reflects the concept of an "ikiryō" (生霊, living ghost) from Japanese folklore.

• Inconsistently, Dan is shown wearing the old-style flak jacket while fighting Chōza during the Fourth Shinobi World War, despite originally being depicted with the pocket-less flak jacket. This discrepancy was not corrected in the anime adaptation.