Black Mountain God frowned upon seeing his enemy. All he could see was a black shadow, and he could not even make out his opponent's face.
Han Sen had also used Dongxuan Aura to hide his entire body, since it had reached that level. He could be properly seen if his opponent was considerably stronger than he was.
And just in case that didn't work, he was clad in armor. There was always the chance his enemy had a geno core that could boost their eyesight, so he made sure to wear armor in the event that might happen.
"My name is Black Mountain God. I hail from Sacred Shelter. Tell me; what is your name?" Black Mountain God was unable to see his opponent's face, and neither could he tell whether the shadow was a spirit or creature. The fact that he might be a human did not even cross Black Mountain God's mind.