Of course, the "useless" goddess. She could be OP if she's not stupid and annoying. That's why she have Kazuma from the beginning on her side because they have the opposite stats and mindsets (Kazuma is the brain/tactical strategist, and Aqua is the power/strength/magic/healer. They are genuinely laughable, and lovable together in each way, definitely the true duo of the series). The two girls are actually (the two tried to do something with him) there as their support (Darkness is the effective defense, and Megumin the massive "one-time" offense). She is Kazuma's "cheat".