This is the Moon elf lich Valindra Shadowmantle. She’s the Overwizard, Master of the North Tower and the coordinator of the Brotherhood’s activities in the northern section of Faerun.
The cosplay was shared by Black Bleach who confirms the very impressive skull masks are latex.
There’s a touch of Photoshop, I think, with glowing eyes in the masks but that’s no bad thing and takes nothing away from either the photograph of the mastery of the costume.
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