Fusion with Samehada is an ability available to the wielder of the sentient sword Samehada, most fully manifested by Kisame Hoshigaki. It allows the user to merge with the blade on two levels: partial and full.
In partial fusion, Samehada transfers accumulated chakra to the wielder, restoring their strength and instantly healing even fatal wounds. This makes the user an extremely difficult opponent who is hard to defeat by ordinary means.
Full fusion transforms the bearer's body, giving it pronounced shark-like features: fins and webbed palms grow, allowing rapid movement in water, and gills form on the neck for breathing underwater. In this form, the user gains part of Samehada's abilities: they can release spikes from their own body, absorb chakra upon any physical contact with an opponent, and also sense the chakra of those around them and evade detection by sensors. This form grants significant combat superiority, but requires full fusion with the weapon, which is available only to a select few.
