Cataphractii Terminator perhaps?
I think it's just another centurion
It seems to have power fists with only two fingers and a thumb and underslung weapons beneath the powerfists. I think it's a centurion, just not as well drawn as the closer ones.
Probably a nu-marine Terminator.
Well at 1St glance it does look like a centurion but from someone who has 15 of them it seriously differs from the current design. For starters its got a set of double shoulder pads which the others in the artwork it's based on specifically don't. Second it's head is a diffrent shape. Third it only has a weapon on its left arm, (the one closest to us) So those are my points, and I'm sticking to em :)
Legio custodes leviathan?
What I meant was Legio Custodes Telemon Heavy Dreadnought.https://17890-presscdn-0-51-pagely.netdna-ssl.com/wp-content/uploads/2017/04/CustodianHeavyDreadnoughtContent.jpg
I wouldn't read into zooming in on art. You do not have to be accurate with art as a persons brain just recognizes a genral shape as simething tangable. That and it would take far to long to render if you made everything super accurate. Its close enough to be a centurion to be it. This seems really clutching at straws.
Looks like one of the mutants Corax accidentally made during the Horus Heresy.