There is some great artwork showing the fragments of humanity left in the Eternal Stormcasts. Take a look with a couple dedicated to the Nighthaunts.
Doesnt that imageabove look like it should be a Space Marine pic?
via the Warhammer Community
"Stormcast Eternals is full of vignettes that take a closer look at the Stormcast Eternals. In the years since their first strikes upon the Mortal Realms, the Stormcast Eternals have become more and more distinct, changed by reforging and clinging to half-remembered tribal affiliations and traditions in an attempt to hold on to their increasingly fragmented memories."