An immense artificial entity resembling at least the upper portion of a humanoid skeleton. Since Baleframe was only ever seen emerging from the Shadowfell Portal at the bottom of the Old Veronese Crypt, it is uncertain whether it has a lower half, or, if it does, what that lower half consists of.
Baleframe consists of a dark metallic framework covered in shards of a marble-like stone, effectively making that framework the skeleton of the skeleton.
While this wiki does not classify Baleframe as a Super Robot, the material used to form the outer shell of Baleframe appears to resemble the marble-like exterior of the Divine Mechanoid Vortemplar.
Baleframe was deployed as part of a mission parallel to the one conducted in the Old Veronese Crypt. Forces, presumably allied with Vecna and Danaus invaded a similar Crypt within the Shadowfell and secured the other side of the portal located in the depths of the Crypt.
Fortunately, The Party was able to shut the portal down and destroy the portion of Baleframe that remained on their side.