RTF is a global modification that replaces all towns in the game.

Why is summoning demons even necessary? Just let there be only summoning of elementals.

Initially, the plan was to replace summoning elementals with summoning demons, but since it will be available to both the Naga and the Alliance, it's not an option.

(Or maybe create a Chaos magic spell that summons demons? It's unlikely that good factions would delve into Chaos magic.)

Chaos is destruction, and summoning demons is summoning. :D