Its the piece with Oly and Prime, the Big guy between them, Figured that's is Be'lakour
His ultimate failure revolved around the Lady of The Lake
The Skull like features, and super high cheek bones match incredibly well
The crown 3rd Eye sorta made sense, but then we releasied its not an Eye, it looks sorta like a heart
Those of you who remember the Endtimes
*END TIMES SPOILER*
He was bound in chains of Light, And Nagash was going to have fun tearing him apart and putting him back together for all eternity. The Deamon was imprisoned in The jewel of Alarielle
Its a fitting punishment, He wanted the 3 eyed crown so badly and now instead he is crowned with his cage, his ultimate failure
Thats what we came up with. The Only hole I found was the reference of Nagash and an "Old Friend" Im not sure where this is said but I know ive read it somewhere, And I dont recall Bel and Naggy being allies at any point,
EDIT*Also the hand looks daemony*