Arcane Annihilation

After channeling the vast amount of raw arcane magics required through the magical artifact, you choose a point you can see or a point you are very familiar with. If you are choosing a point you cannot see, roll a percentile die to determine whether your targeting is successful: 90% chance to succeed if it is a place you have been to at least 3 twice, 60% chance if it is a place you have been to once or seen from a distance, 40% chance if it is a place you know the general geographical location of, and 20% chance if it is a place you have been told about or only know the name of. On a failed targeting, the spell is cast at a random target of the DM's choosing with increasing distance from the intended target based on unfamiliarity. The artifact used in the casting of this spell disintegrates after the casting due to the tremendous amount of power channeled through it.

Upon casting, you create a ball of pure, undiluted arcane energy and send it to the designated point. When it lands, every living creature within a 5,000 radius sphere centered on a point must succeed a dexterity saving throw or take 30d10 force damage, halved on a success. Creatures that are inside of a structure make the throw with advantage and take 1/4 damage on success. Structures in the blast radius take 20d12 force damage, and all targets take 20% less damage for each 1,000 foot increment from the center they are (to a minimum of 40%). Creatures that are killed by this spell are instantaneously vaporized by the sheer force of the raw magical energy. Any magical artifacts valued less than the one used in the casting are instantly disintegrated by the blast.

Additionally, for 1d6+1 days after the blast, all magical artifacts valued more than the one used in the casting (as well as any potions survivors might have on their person) are temporarily rendered magically inert and useless while in the blast zone. During this time, the blast zone is also considered difficult terrain and any spell in the area requires a successful DC 20 concentration check in order to cast as the leftover arcane forces interfere with the manipulation of magic.