In fanfics, anything is possible. Since it's a fictional creation, an author could write a scenario where Naruto has the ability to use Bankai. However, in the original Naruto and Bleach universes, their powers are completely separate, with Naruto having chakra - based ninja abilities and Bankai being a high - level power in the Bleach world.
In the manga, Senjumaru did not employ Bankai. The character's abilities and actions were depicted differently without resorting to this particular power.
Shinji did use his Bankai in the manga. It was a crucial moment that turned the tide of the fight. The Bankai's power and unique abilities were showcased, adding an exciting element to the story.
Yes, in some fanfictions, Naruto is given a Bankai. Fanfiction writers often like to cross - over different anime concepts. They might give Naruto the power of a Bankai from 'Bleach' to create unique and interesting storylines. This can lead to some really cool battles and character developments that you wouldn't see in the original Naruto series.
In fanfiction, it usually works by combining the elements of Naruto and the Senbonzakura Bankai from Bleach. For example, Naruto might be able to summon cherry blossom - like blades similar to how Senbonzakura Bankai works in Bleach. These blades could have special properties like being able to cut through chakra or being able to move at super - fast speeds.
Luffy uses Gear 5 in a significant battle towards the later part of the manga. But the exact chapter or arc can vary depending on how you're reading it.