Your city will level up as it is attacked. While you cannot directly control the city’s defence outside of building its custom deck, you can view how it fares when attacked and collect XP for every battle fought. Victories grant higher rewards, but every battle helps.
Tap on the Battle Reports button on the City Screen to view any battles your city has been in.
The outcome of your city’s battles will be shown on the battle report banner.
Tap on the banner to view the full battle report and the rewards for this battle.
Tap on Collect All to collect your battle rewards and XP!