Nanomachines

Nanomachines aka Nanites are tiny, molecule-sized robots able to modifiy the DNA structure and to manipulate a body from the inside; which makes them frequently used in science fiction stories. Nanomachines serve as a critical plot device all around the story of the manga Black Cat, and its anime adaptation, as the series' main villain Creed Diskenth wants to use them in order to become immortal and to create an army of super soldiers. As the story progresses, many types of nanomachines are introduced to fulfill various purposes, which always revolve around modificating someone's body to improve their physical condition and/or their fighting skills.
 * Name: Nanomachines
 * User: Eve, Creed Diskenth (Temporarily) Train Heartnet (Temporarily, Manga Only).
 * Type: Nanotechnology
 * Debut (Manga): Chapter 5
 * Debut (Anime): Episode 3