Magnus, listen, where is my hero and what should I do?

Suddenly, you hear the voice of the Overlord in your head; you did everything you could, and you gained +2 levels. Suddenly, you see a group of dwarves, the Mountain Guardians, running towards you, shouting, "Burn in the fires of Urgash, undead!" Actions?

We'll take the artifact – it will weaken the enemy army. We need to hide it somewhere or use it against the enemy. I approach the Emperor.
- This magical sword, I don't know how to use it (I give it to the Emperor). You are wise and know about artifacts, and I will go to the moat.

Oh, my god, this is the sword of Kha-Beleth himself, enchanted with the flames of Urgash, the most terrible sword. He must be here. I cast "Destruction of the Unbelievers" on the Guildmaster's territory. He opens a portal and disappears. You approach the moat; a hail of arrows from skeletal archers covers you. Suddenly, a protective field appears before you, created by the Emperor to protect the city. Suddenly, you feel a strong force field, an earthquake, and demons burst from the flames. The Emperor banishes them and calls upon the mercy of Silanna. The earth is restored, but the embodiment of Urgash appears, incinerating the city walls. You receive 50 HP. The Emperor creates a beam of holiness and incinerates the embodiment of darkness with light. Suddenly, an army of darkness appears from the forest. With the Book of the Dead, they resurrect all forces in the form of undead. A fog of death descends upon the city; all living creatures are transformed into undead. What are your actions, Alexander?