I think Reiko isn't really much an "anomaly". Magical powers are powered by negative human emotions. After thinking she's become Jaryuu's "kin", she became more arrogant and hostile because of her loyalty and assumptions (ayyy chuuni loli). She introduces herself to everyone as Jaryuu's kin, she has caused destruction, and inflicted fear using Jaryuu's name. It could be said it's natural for her to unconsciously suck in the "fear of Jaryuu" power instead of going to the pacifist vegan lizard.