From their website:
With her creation Belphagor at her side, Bethayne stalks the battlefields of Immoren to bring death and destruction to the enemies of Everblight. Bethayne can meld with Belphagor, donning the mighty warbeast’s flesh like an enormous suit of scaled armor. The two become one, acting in concert as a single individual, mingling a warlock’s sorcerous power with the brutal onslaught of a warbeast’s fury.
Update: the model includes parts and magnets to allow you to swap out forms to show the conjoined version of Bethayne and Belphegore.