Yes, there is a Ninja Kamui manga. It has gained popularity for its action-packed scenes and interesting character developments. Many fans enjoy collecting and reading it.
Naruto using Kamui could change the power dynamics in the Naruto universe in the fanfiction. His battles would become more unpredictable. For instance, against strong opponents like Madara or Kaguya, Kamui could be used in creative ways. He could use it to send parts of their attacks to another dimension, or quickly dodge attacks and counter - attack from unexpected angles. It also might make his allies view him differently, as this new power is something very different from his normal ninjutsu.
In many fanfictions, Naruto might initially discover Kamui through an encounter with Obito or Kakashi. Maybe during a battle where he witnesses the power of Kamui first - hand, and his inquisitive nature leads him to start exploring how to learn it.
In some fanfictions, Naruto might acquire the ability to use Kamui through a special encounter. Maybe he meets an ancient sage who imparts this power to him, seeing Naruto's potential and his need for an edge in battles against powerful foes.
One challenge could be controlling the space - time aspect of Kamui. It's a very complex jutsu, and Naruto, who is used to more straightforward chakra - based attacks, might struggle to understand the intricacies of warping space and time.
I'm not really familiar with this specific 'Kanna Kamui Lemon Fanfic'. But if it's a fanfic, it might be a creative work by a fan that could explore different aspects of the character Kanna Kamui. It could potentially have interesting plotlines, unique character interpretations, or explore new scenarios for the character. However, without actually reading it, it's hard to give a more in - depth review.