The gamepad plays an important function in the game. Since the gamepad has a dedicated function and not just an optional accessory, the game has no gamepad-only mode, unlike other Wii U titles.
Topics are instant messages you get from your party members and allies. This gives some extent of immersion in the game with some limited options of choosing a pre-made response at times. The most useful use of the topic function however is when you unlock the Carnage/ Radiant Unity Notification Function. With this function on, you'll receive instant notifications when you have enough performa and materials to unlock new Carnage and Radiant for your characters. Since mastered Carnage (weapons) offer no new skills to inherit, it's often a good idea to return to your headquarters to create a new Carnage.
In the gamepad, you can keep track of the active storyline and its developments, keeping you updated and on track of your story progress. You can also review the previous storylines that you have already completed. Unfortunately, you can't keep track of your Requests in this screen.
The gamepad gives you access to the maps of the locations and idolaspheres you have visited anytime. You can change the level and the layout of the maps will depend on how much you covered during your exploration. There are also helpful icons and legend that will help you find your way around both hostile and safe environments.
When browsing through different enemy types in the Analysis option from the main menu, the gamepad displays in-depth information about that specific enemy, ranging from the basic stats, strengths and weaknesses, skills, and many more.