RPG on the Portal.

That’s it, they’ve gotten on my nerves. I’m casting a rune. And I’m uttering a sacred word. All demons – 10 HP.

The imps immediately headed to Urgash, but for the other demons, the spell wasn’t fatal... and they rushed at you...
P.S. maybe it’s time for the cavalry to join the battle? And to scatter the demons with a gleaming wedge?

Added 1 minute ago

- Catapults, to battle! - Boulders were lowered one after another onto the wall, crushing the ancient stone. The gates were about to fall under the onslaught of falling boulders.

But some force kept the gates intact, even despite a direct hit from a huge boulder... The walls were also crumbling, but so far there hadn’t been a single serious breach... for the army to break into the city... It seems this is Urgash’s power...