The Emperors appearance molding to the viewers preference so for some Primarchs he basically looks identical to their parents. For Angron who has the nails distorting psychic intrusion it's just a distorted homunculus of his dead slavekin constantly morphing to find something 'acceptable' which is why he's so wary of him initially apart from everything else. it's also interesting to have the loyalist Primarchs being like that because on a subliminal level The Emperors resembles their actual deceased parents. i will draw it when i have free time in a little while. Also isn't it interesting to think of the emperor at some point a victim of memetic interpretation where he molds to humanities overall perception- maybe perhaps why he doesn't want to ascend to a warp entity and be entirely subject to it beyond what he already suffers


















