Envoy uses Senjutsu in a non traditional way. Which means that he does not take the appearance of an animal and does not gather just any nature energy. Upon being unsealed and awakened he was blind for quite some time due to not being experienced with the Sharingan transplanted into him. To adapt Envoy found a way to use his affinity to earth by sending out small burst of chakra waves from the sole of his feet that spread through the land underground and it bounced of things and came back to him like a sonar. Once he was adept to the technique he noticed that each wave he let go came back with a good amount of nature chakra.