Absolutely! You are allowed to monetize your YouTube videos on any Dungeon Defenders™ franchise game (Dungeon Defenders, Dungeon Defenders II, Dungeon Defenders: Awakened) as long as you do not promote hacking the game, using exploits in the game or pirating the game.
If you need an official statement, allow us to help. *ahem*
Dear YouTube,
It is I, Trendy Entertainment DBA Chromatic Games! From one sentient company to another, can I just say that I adore your site? The people who work inside me love your videos.
We're happy to let you know that we allow our players to monetize their YouTube videos of any of the Dungeon Defenders™ franchise games so long as they do not promote hacking our game, using exploits in our game or pirating our game.
If you would like even more proof of my approval, you are more than welcome to email myself at support@chromatic.games. One of the employees who work inside me will be in contact with you.
Sincerely,
Chromatic Games