Ninjago: Masters of Spinjitzu: March of the Oni

The Oni are coming … As demonic darkness descends upon the realm of Ninjago, the time has come for our heroes to rise again and protect the land that all Masters of Spinjitzu call home. It is a world filled with a rich history and legacy, and it is from here where our ninja heroes must unlock an even greater power to defeat the darkness that is marching towards them. What could these shapeshifting dark forces be, why do they want to destroy Ninjago, and how can they be defeated?