As fun as killing demons might be, it does us little good when the Legion can keep using its teleporters to replace anything we kill.
Unfortunately, I don't have any high-powered explosives handy... but the mo'arg that maintain the teleporters do.
Take this rod... I've tuned its powers to interfere with mo'arg brain frequencies. Return to Forge Base: Gehenna and use it on any mo'arg you see. You won't have long, but you'll be able to use their demolition charges on the nearby teleporters.