The current edition of Dungeons & Dragons only includes spells that reach level nine, but there was a time when D&D spells went to level 10 and beyond. The average D&D game never reaches high levels of play, but that doesn't stop many players from dreaming of reaching the fabled ninth level of magic and beyond.
Ninth-level spells in D&D include some incredibly powerful effects, like time stop, gate (which creates a portal to another dimension), and meteor swarm (which unleashes a torrent of fireballs). This level also contains the wish spell, which gives the player the chance to ask for anything they want. Wish often isn't as beneficial as it seems, however, since many DMs aren't so benevolent. A player who asks for a +5 flaming greatsword might summon it with wish, but they'll also get a demon prince holding it along for the ride.
High levels of play can involve all kinds of ridiculous items, such as fabled +7 D&D weapons, but spells have a hard limit on how far they can go. This wasn't always the case, as there was a time when spellcasters could reach levels of power far beyond what the mages and priests in the current edition of Dungeons & Dragons are capable of.
D&D's Forbidden Spells Of Netheril
The second edition of D&D had an in-universe explanation as to why spellcasters couldn't cast 10th-level spells. In the Forgotten Realms campaign setting, the empire of Netheril was ruled by incredibly powerful mages. The Arcanists of Netheril created floating cities that cast a great shadow on the land below. These amazing wizards had access to 10th- and 11th-level spells. The 10th-level spells included Lefeber's weave mythal (which creates a powerful ward around a city), Proctive's move mountain (which removes the top of a mountain), and Tolodine's killing word (which kills all lifeforms across a massive area). The 11th-level spells included Proctiv's breach crystal sphere (which prevents all interstellar travel to a world), and Mavin's worldweave (which alters the weather across a massive area),
A single 12th-level D&D spell existed, and it resulted in the destruction of Netheril. Karsus' avatar was a spell that allowed the caster to turn into a god. Karsus used this to usurp the position of Mystryl, the goddess of magic. The spell worked, but Karsus was unable to maintain the Weave (the source of magic in the Forgotten Realms), causing the cities of Netheril to crash into the ground. Mystryl was reborn as Mystra, and she created the ban on spells above the ninth level.
D&D's Powerful Epic Spells
The third-edition Player's Handbook only included spells up to level nine, but a supplement called the Epic Level Handbook included a new system for spells beyond the realm of normal mages and priests. Once a character reached level 20, they could take the Epic Spellcasting feat. This gave them separate Epic Spell slots, which were equal to a relevant skill (such as Knowledge Arcana for Wizards) divided by 10. The character then had to research an Epic Spell, which involved spending cash, experience points, and time. The weakest Epic Spell, peripety, cost a quarter of a million gold pieces to research.
In order to cast an Epic Spell, the character had to a Spellcraft check. Peripety only had a check of 27, which was easy to for a level-20 spellcaster. The stronger Epic Spells were another story, with Dire Winter having a check of 319. The effects of Epic Spells are well worth the asking price, as some of these D&D spells are apocalyptic in nature. For the cost of 450,000 gold pieces, 18,000 experience points, and a Spellcraft check of 50, the player could cast dragon strike, summoning 10 adult red dragons to their side - and that's one of the weaker Epic Spells in the history of Dungeons & Dragons.
Source: Netheril: Empire of Magic, Epic Level Handbook
