The Colossus's blade is predominantly orange with silver edges, and is slightly curved. The counterweight flares outward slightly and is also orange with silver edges. The handle is a smooth, black rod with an orange spike set in its pommel. The tip of the handle is also orange.
An Oni is a type of Japanese monster resembling an Ogre. In Final Fantasy X, Auron possesses the "Ogre Blade", based on the same name. A "colossus" is anything of gigantic size. The name could also reference the Colossus of Rhodes, a gigantic statue of the Greek Helios, and one of the Seven Wonders of the Ancient World.
The Colossus's normal ground combo starts with a one-handed upward diagonal slash and ends with a powerful, two-handed downward slash. The combo can be activated after the first upward slash, and consists of another one-handed upward slash, followed by a leap and a powerful, two-handed downwards slam.
The Colossus's aerial combo consists of a two-handed upward slash followed by a powerful, two-handed downward slam.