You speak one to three Words of Power in fundamental Infernal. Around you, there appears some number of orbs created from flaming chaotic energy. You may direct these orbs in accordance with the three core layers of hell, granting different effects.

Avernus (level 3 spell slot): Six orbs hover in the air and orbit you for the spell’s duration. When you cast the spell — and as a bonus action on each of your turns thereafter — you can direct up to two of the orbs, sending them streaking toward a point or points you choose within 120 feet of you. Once an orb reaches its destination or impacts against a solid surface, it explodes, shooting out chaotic energy. Each creature within 5 feet of the point where the chaotic energy is released must make a Dexterity saving throw. A creature takes 2d6 fire damage on a failed save, or half as much damage on a successful one.

Stygia (level 6 spell slot): Nine orbs form into a swirling storm of chaotic energy. You may direct this storm to a location within 150 feet of you. Each orb affects a 10-feet cube around it with blazing chaotic energy. You may arrange these nine orbs as you see fit, as long as one orb is always connected to another. Each creature in the area must make a Dexterity saving throw. It takes 10d6 fire damage on a failed save, or half as much damage on a successful one. The fire damages objects in the area and ignites flammable objects that aren’t being worn or carried. If you choose, plant life in the area is unaffected by this spell.

Nessus (level 9 spell slot): Blazing orbs of chaotic fire plummet to the ground at four different points you can see within 1 mile. Each creature in a 40-foot-radius sphere centered on each point you choose must make a Dexterity saving throw. The sphere spreads around corners. A creature takes 40d6 fire damage on a failed save, or half as much damage on a successful one. A creature in the area of more than one fiery burst is affected only once. The spell damages objects in the area and ignites flammable objects that aren’t being worn or carried.