His lightning angel armor would protect him if he decided to venture into the body of the giant snake made of poison. But he didn't want to risk that kind of danger and was content with slowly melting the giant snake.
The lightning domain was also consuming a lot of his energy, just as the lightning domain was causing Green Viper to consume a lot of energy to keep the giant snake intact. So it is the one with the most energy that will win the fight.
Arthur did some calculations to determine who would lose if the fight continued like this. After his calculations, he concluded confidently that he would win.
His confidence came from the fact that he had a perfect golden core, which is bigger than Green Viper's core. So he has a larger energy capacity and a higher energy regeneration than Green Viper.
