Of course, when vocational power branches off, advancing from D-level 'Lone Shadow' to C-level 'Dark Priest', 'Dark Witch', 'Dark Knight'...this is also orthodox, only that the conditions of the contract are freed from the restriction of having to be a demon.
The 'Grand Dark Priest' held by Ye Liuying, is a transformative version of C-level 'Dark Priest'.
She possesses passive abilities like 'Source of Darkness' and 'Shadow Form', making her a controller of darkness, capable of assimilating Contracted Spirit Fond Spirits and initiating dark remodeling without causing harm.
She can draw on the dark power to heal herself and the Contracted Sprit Fond Spirits, while forming a strong resistance to, and even immunity from, the dark elements at the same level or below.