Also I emailed Namco about the game and the ads and I was told this.......
"Thank you for contacting Namco Bandai Games America Inc. Customer Support. The free version of the game that we release for the Android platform is basically an extended demo. You can play any one of the 4 classes up to a certain point in the game. At that point you’ll need to purchase the class you are playing in order to progress through the rest of the game. If you purchase one class, it will remove ads from the World Map. If you purchase the Full Game Unlock it will unlock everything for the entire game and remove ads completely. "