The Akatsigan belongs to the Uchiha clan. Only 3 shinobi can use this dojutsu at a time but the user has has to have acess to every chakra nature. The Akatsigan can destroy any type of matter. The Akatsigan has very powerful genjutsu and can see anything in slow motion.The way the akatsigan works is it sends chakra to a body of atoms or individual atoms then splits them with something similar to a chakra blade, then it repeats this process until there is nothing left. this process is said to be near instant and faster than the flying thunder god or body flicker.
The akatsigan has a very distinct mode of chakra called ACM (Akatsigan chakra mode) in this mode the user can things in even slower motiong and can for instance watch light fill a room and a body flicker get from point A to point B>the color of ACM can vary for the user but its typically a very dark red with spots of light red.