Gloom, Melancholy
noun, な adjective
A shade energy is a shady feeling. It's a feeling of gloom and melancholy.
いんき
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
アイツのYoutubeビデオを見るまでは、てっきり陰気な男だと思っていたよ。
I was certain he was a melancholy guy until I saw his Youtube videos.