Because the modellers at bE seem to be clueless when it comes to eldar. They make a kick ass death jest mask but put it as a SHOULDER for DR meanwhile the basic helm looks like a fucking marshmallow.
It's the DR exarch shoulderpad: What I don't like of the EC eldar models is the scratched metallic texture of their armors. They use wraithbone, no metals.
I would start a Lvl1 female Eldar all over again for this model. And pay 10k RTC or more. Edit: I already did that now