Naruto is home to some of the most outrageous powers in shonen history. There's the Rinnegan, Sharingan, Byakugan, and many others that grant an absurd amount of strength to their wielders. Considering the sheer number of powers in the story, it's perfectly normal for the author to omit one or two powers due to time constraints or other reasons.
Sadly, one of the abilities that was sacrificed was the legendary Tenseigan of the Otsutsuki. It was introduced in Naruto The Last, but instead of being utilized in other arcs, it was abandoned completely.
What Is The Tenseigan, And How Can It Be Awakened?
As previously stated, the Tenseigan was introduced in a movie called Naruto: The Last. Much of the movie takes place on the Moon, which is home to the descendants of Hamura Otsutsuki. Fans may remember Hamura as Hagoromo's younger twin brother. The two fought Kaguya Otsutsuki for months in hopes of bringing her down and freeing the world from her reign. Due to Kaguya's overwhelming strength, the brothers had to struggle a lot and dig deep to get a result. Once they had beaten and sealed Kaguya forever, Hamura decided to go to the moon to make sure that she wouldn't escape ever again. Meanwhile, Hagoromo stayed on earth to start Nishu and later came to be known as the Sage of the Six Paths.
While Naruto focused mainly on Hagoromo and his descendants, Hamura was ignored for almost the entire story. However, this changed in Naruto: The Last, where the villain was none other than Toneri Otsutsuki, a descendant of the legendary Hamura Otsutsuki. Before dying, the latter left behind a will for his descendants, but sadly, Toneri misinterpreted it and started working on a way to carry it out. He learned about the Tenseigan and how to obtain it. According to the source, a person could only awaken the Tenseigan if they had the chakra of Hamura Otsutsuki and implanted the Hyuuga's Byakugan into their eyes. Toneri wasted no time and decided to kidnap Hanabi Hyuuga from the Hidden Leaf. He then stole her eyes and implanted them into his own sockets. By doing this, Toneri met the prerequisites to awaken the Tenseigan. However, he didn't awaken the Tenseigan immediately. Instead, he had to wait a few days for the process to be completed. Whether the restriction applies to everyone remains to be seen.
The Tenseigan Can Wipe Out Entire Nations
Toneri may have been in pain for several days, but he was more than happy to compromise because the Tenseigan was just too powerful an ability. The Dojutsu allows its user to enter the Tenseigan Chakra Mode, in which the user's body is covered with cyan chakra. This particular ability enhances the user's physical abilities immensely. The user becomes stronger, faster, and more durable. They also receive the Truth Seeking Balls, a unique tool that has attacking as well as defensive functions. Due to their composition, any normal human being who touches the Truth Seeking Balls is turned to dust instantly. Toneri could also compress chakra and then combine it with the Truth Seeking Balls to create a massive sword that could slice the moon into two.
It's safe to say that with such an absurd level of strength, Toneri could have wiped the floor with most of the ninjas in Naruto. Unfortunately for him, his opponent was none other than Naruto Uzumaki. The hero combined the power of the Nine Tails with Six Paths Sage Mode, and it proved to be sufficient in taking down Toneri and saving the world from yet another disaster. Following the conclusion of the movie, the Tenseigan disappeared, and to this day, it still hasn't returned. But there is a genuine possibility that the Dojutsu might make a comeback.
Ikemoto Can Bring Back The Tenseigan In Boruto
Boruto: Naruto Next Generations is the perfect place for Tenseigan's comeback. Firstly, it is a Dojutsu that is linked to the Otsutsuki clan, and considering there are so many of them in Boruto, it wouldn't be outlandish or unnatural to include the Tenseigan in the story. Fans have already seen two new Dojutsu in Kokugan and Senrigan, which belong to Isshiki Otsutsuki and Eida, respectively. Both of the ocular powers are extremely potent, and they make their users nearly invincible. So, the introduction of the Tenseigan won't ruin the power dynamic that has been set in the series. Secondly, there are a few characters in the series who could do with a power-up. Someone like Himawari would be the perfect fit. She is already a Hyuuga, and all she requires is Hamura's chakra.
Lastly, the introduction of the Tenseigan would make Toneri and Hamura relevant to the story again. Both of them are canon characters but have been rather mistreated by the authors. However, there is still time to undo the mistakes and give the two characters, especially Toneri, more screen time. The author can tie in Toneri's story with that of the other Otsutsuki characters in the story.
Aside from Toneri and Hamura, there are several other characters who would greatly benefit from having a bigger role in the story. Ikemoto has sadly sidelined way too many old-generation characters, including Naruto and Sasuke, both of whom are considered the core pillars of the series' success. In the first part of Boruto, Ikemoto made many reckless decisions that negatively impacted Naruto and Sasuke. He made Naruto lose the Nine Tails in the most bizarre fashion possible, and if that wasn't enough, the author also made sure that Sasuke's Rinnegan was destroyed. The two heroes losing their most significant powers did not go down well with the audience, especially since it was a symbol of their hard work and their journey in the Naruto series. To rob the heroes of their powers was extremely disrespectful. Even if Ikemoto wanted to sideline them, there were better ways to do so.
The other older-generation characters don't have the necessary means to deal with the enemies in Boruto, so it's become impossible to include them in the story, as they would be swept aside. However, there isn't anything stopping Ikemoto from giving them power-ups. At least someone like Konohamaru and Sakura should be more involved. The latter is a member of the legendary Team 7, and to see her in a reduced role is really troubling. Meanwhile, Konohamaru's case is that of ruined potential. At the beginning of the story, Konohamaru was a Jonin, so fans had high expectations from him. But he was quickly surpassed by his students, so he couldn't even stay relevant for long. However, there is still a chance that Sakura and Konohamaru might be redeemed.