The Eye and the Hands (Part 1)
Instead of destroying them, the Plague Arrows turned the mages back into living beings by balancing the scales. At the same time, physical contact allowed the souls that haunted Grem and Xennon to unleash their fury.
The bodies of the two mages constantly rejuvenated themselves thanks to the mass that had been bestowed upon them at birth by the ritual. The life force and light element that coursed through them had been stolen as well and kept in check by the Forbidden Magic empowering Kolga's sun.
The souls used the death energy flowing from the cracks in Lith's life force to get ahold of what belonged to them now that the Plague Arrows had temporarily disrupted the effects of the ritual.
Lith could feel the shades begging him to grant them substance and he did. By infusing them with Spirit Magic, the souls turned into Demons of the Darkness who used their powers to retrieve all that Forbidden Magic had taken from them.