This build is oriented for being able to quickly transform into shadow, gloom was more of an afterthought so energy management will be pretty difficult, that said, gloom is pretty insane due to the high strength causing enemies to almost completely freeze. Umbral vit needs to stay rank 9 to not go over 78.
(Disclaimer, I am not some build genius so this is likely not perfect, if you have feedback feel free to share, for example if you have ideas for what should be replaced to help with efficiency, I am all ears!)