As players learn more and more potent spells, the amount of damage these spells can deal grows exponentially as well. At the upper levels of play, the damage being tossed around is almost absurd, and only the toughest of enemies will be able to withstand the onslaught of a high-level spellcaster in D&D 5th Edition.
Updated September 16, 2022 by Declan Lowthian: Many of the highest damage spells are restricted to arcane casters like wizards and warlocks, so this list was expanded to include spells from other classes, as well as some spells that deal damage in less direct ways than others.
Getting damage out of True Polymorph takes some creative thinking, but it will be instantly rewarded. This spell can easily be used to transform a major boss enemy into something as unthreatening as a toad, but anyone looking to use it more offensively will be able to do so. True Polymorph, available to bards, warlocks, and wizards, can turn a creature into any other creature with equal or lower challenge rating/level.
True Polymorph can turn a 20th-level character into an ancient white dragon, whose breath weapon attack deals 16d8 cold damage. Other fun options include a pit fiend, which attacks four times per turn for a total of 12d6 + 16, 2d8 +8, and 3d20 +8 damage, or a nightwalker, one of the most powerful undead in D&Dthat obliterates life with its very presence.