Responses
I think it's the side effects of something awakened by Lou, like he can't control his feelings or bloodlust.
I think it's her fault actually. She was the one thats causing his eye to turn purple and Lou was completely normal before they met her #－.－)
I disliked that purple haired girl from the start but now I hate her!! What did she do to him? Why is he acting like a follower of demon king? I hope he gets away from her influence soon