'It's finally dead.'
Arthur stored the corpse in his storage and disappeared from that area, even the nearby old man who watched the whole fight, was startled as he suddenly lost track of Arthur.
No one would expect Arthur to transform into an insignificant sprout deep underground. He spent every last bit of effort to reduce his stats and reduce his presence. Not even the ancestor of the Mirage Era Hall discovered him, so it isn't surprising that the blind man couldn't find him.
Actually, Arthur didn't know that he was being watched, he only did that because the fight attracted too much attention. He could feel several gazes belonging to the elders of the Golden Earth Sect focus on him. They just didn't dare join the fight.
He didn't suffer any serious frontal attack but creating that Thunder Dragon and using the withering effect of the Death Magic exhausted him.