Thundarr the Barbarian (1980)

S2E6 Master of the Stolen Sunsword

In a confrontation with Yando, a self-proclaimed wizard wielding strange magic, Thundarr is hit by a bolt of red negative lightning that greatly weakens his Sunsword. To regain its full strength, he must retrieve it from the nearby Pool of Power. However, Yando seizes the opportunity to steal the pool's energy, intent on claiming the Sunsword's power for himself.