Welcome to Demon School! Iruma-Kun 9

The story follows Iruma and his friends as they celebrate their exam success with a trip to Walter Park, an amusement park in the netherworld. Unbeknownst to them, the park is constructed over a prison fortress where inmates are plotting a dangerous scheme. As they enjoy their break, the looming threat from the fortress adds a layer of suspense and adventure to their outing, blending fun with unexpected peril.