The Catacombs is a location in Ben 10 Ultimate Alien: Cosmic Destruction. The Catacombs are a dilapidated place. Torches, bats, and rats can be seen in the Catacombs. Ghosts can also be seen floating around.
On the left of the first save slot is a breakable wall inside which the first card is found
After beating Vulkanus, on the platform on the right, behind a coffin is the second card
After being introduced to the Spartan enemy and fighting a couple of them you will enter another puzzle room. Before doing anything, head downstairs and turn 180 degrees to see the third card inside some bars. There is an opening in the bars through which you can walk to collect your prize