Complex sentence: In one anime episode, however, Kasumi has a battle aura surrounding her because of Happosai's actions, while Nabiki simply punches him away, and he enthusiastically attempted to peek on Nabiki when he thought she was naked in the bathhouse early in the series.
Split into simpler sentences: In one anime episode, however, Kasumi has a battle aura surrounding her because of Happosai's actions, while Nabiki simply punches him away. He did, however, enthusiastically attempt to peek on Nabiki when he thought she was naked in a bathhouse early in the series.