Zelly-fangirl
So for the Slayers rp. You could of course have the traditional "big bad bent on summoning super powerful god/demon/something very not good" in the same vein as Rezo. I was somehow thinking evil cult myself. Or said cult looking to collect some evil ancient items while the heros try to destroy them. I could see that working in the realm of Slayers.
Totally doing that. Now to rewatch every episode to get a good flow going. XD