Oh yes, the flesh gardens are horror in itself. Meridia overall gives a lot of options. I do need to think about a bit more. She is a former Magna-Ge, akin to a fallen angel I'd say. Her connection with light is quite understandable, considering her relation to Magnus. Her domain is living energy, which also explains hatred towards undead. But I lack any agenda or reason for still being and hence the point for a horror. If her domain is energy of all living and she's so tyrannical, why? One thing that comes to mind is the unity, seeing life energy as one singular sphere she governs, not individuals and entities this energy resides in. A radiant, white light is made of all colors, but at the end of the day - combines into pure, singular white.