>>55118060Infernape's fire type is supereffective over Torterra's grass typing but also weak to it's ground typing.
Empoleon is supereffective on Infernape's fire typing as a water type but it's steel type makes it weak to Infernape's fighting type.
Torterra is a grass/ground type, making it 4x weak to Empoleon's and Infernape's ice type moves, but at the same supereffective on both due to steel and fire's weakness to ground type. It's all balanced.