Greninja is a Water/Dark-type Pokemon and the final evolution of Froakie. In the anime, Ash's Frogadier evolved into Greninja and possesses a very unique form called Ash-Greninja through the process of Bond Phenomenon. After the Kalos League and the Team Flare crisis ended, Team Robot gives Greninja a communicator so whenever they need it they will call it. Princess Anna also owns a Greninja who appears to be a descendant to Ash's Greninja.
Gallery
Ash Greninja form