Magic: Spelljammer 5e Conversion


Converting the Spelljammer rules for magic over to 5e is probably the simplest thing I’ve had to do. Magic in the Second Edition Advanced Dungeons & Dragons rules is essentially the same as it is in the 5e rules. The Spelljammer campaign setting didn’t really add any new rules for magic use so much as it added restrictions to the existing rules. So my conversion of the rules solely hinged on which restrictions to keep and which to jettison. 

There were two magic restrictions introduced in the original Spelljammer rules; restrictions on clerical magic and restrictions on magic in the Phlogiston. I’ll deal with the restrictions on clerical magic first. The individual Crystal Spheres in Spelljammer represented separate campaign worlds and therefore they each contained that world’s pantheon of gods. In Spelljammer it was assumed that the reach of any god’s power did not extend beyond the Crystal Sphere that they existed in. Because Clerics and Paladins derive their spell-casting abilities from service to these specific gods they were not able to regain spells above 2nd-level when traveling beyond their home sphere.

This restriction was essentially hand waved away with the introduction of the new 2nd-level spell Contact Home Power. Casting this spell allowed a Cleric or Paladin to normally regain all of their spells for one week so long as they remained in the Crystal Sphere where the spell was cast. You can see where this restriction and work-around don’t seem to have any thematic impact on a Spelljammer campaign. Any intelligent player is going to take Contact Home Power as a known spell making the original restriction obsolete. For that reason I have chosen to completely remove any restrictions on clerical magic in foreign Crystal Spheres.

The second magic restriction involved regaining spells and casting of certain types of magic while traveling in the Phlogiston. The Phlogiston in Spelljammer was described as a region that is cut off from divine powers and the various other planes of existence. Conjuration or summoning magic that relied on contacting extra-planar beings, elementals or gods did not work in the Phlogiston, nor will any magic that transported a character to any extra-dimensional space or other plane. This rule also applied to specific magic items that used similar types of magic. The nature of the Phlogiston also prevented Clerics and Paladins from contacting their deities to regain spells whether Contact Home Power was cast or not.

I like this rule since it presents an additional challenge for players traveling in space. That’s why I have chosen to keep it for this conversion and expound on it to make it more 5e friendly. I went through all of the spells and magic items to come up with a list of ones that would be affected. Some of them will fail altogether while a few ended up slightly more limited. The restrictions on regaining spells needs to be changed to slots for 5e and also expanded to include Warlocks.

Magic functions exactly the same from Crystal Sphere to Crystal Sphere. Spells that can cast in the Forgotten Realms can also be cast on Krynn or any other world.  However, magic in the Phlogiston is a different story altogether. The Phlogiston is cut off from any of the major powers that inhabit the Crystal Spheres. Clerics and Paladins are unable to commune with their chosen deities while traveling through the Phlogiston and Warlocks are cut off from their patrons. These classes are unable to regain exhausted spell slots while outside of a Crystal Sphere, but may continue to use Cantrips. Class features are unaffected by this restriction.
The Phlogiston is also isolated from the other planes of existence. The peculiar nature of the Phlogiston makes it impossible to cast any spell that conjures celestials, elementals, fey, fiends, or any other extraplanar beings. Devices or spells that allow for planar travel will not function in the Phlogiston nor will any device or spell that creates extradimensional space.

Spells in the Phlogiston

The following spells will not function in the Phlogiston:
  • Astral Projection
  • Augury
  • Banishment
  • Blink
  • Commune
  • Conjure Animals
  • Conjure Celestial
  • Conjure Elemental
  • Conjure Fey
  • Conjure Minor Elementals
  • Conjure Woodland Being
  • Contact Other Plane
  • Demiplane
  • Divination
  • Etherealness
  • Find Familiar
  • Find Steed
  • Gate
  • Leomund’s Secret Chest
  • Maze
  • Mordenkainen’s Faithful Hound
  • Mordenkainen’s Magnificent Mansion
  • Planar Ally
  • Planar Binding
  • Plane Shift
  • Spirit Guardians
The following spells have limited effects when cast in the Phlogiston:
  • Banishing Smite– Reducing the target to 50 hit points or fewer does not banish it.
  • Imprisonment– You may not choose Hedged Prison.
  • See Invisibility– You are unable to see into the Ethereal Plane
  • Sending– Messages have no chance of reaching a target on a different plane than you.
 The following magic items will not function in the Phlogiston:
  • Amulet of the Planes
  • Bag of Devouring*
  • Bag of Holding*
  • Bowl of Commanding Water Elementals
  • Brazier of Commanding Fire Elementals
  • Censer of Controlling Air Elementals
  • Cubic Gate
  • Heward’s Handy Haversack*
  • Horn of Valhalla
  • Iron Flask
  • Mirror of Life Trapping†
  • Oil of Etherealness
  • Plate Armor of Etherealness
  • Portable Hole
  • Quiver of Ehlonna*
  • Stone of Controlling Earth Elementals
  • Well of Many Worlds
*The extradimensional spaces housed within these items cannot be accessed from the Phlogiston, but anything previously stored within them remains within them.
Any creature already trapped within the mirror’s extradimensional cells remains trapped while in the Phlogiston.

Magic Items in the Phlogiston

The following magic items have limited use in the Phlogiston:
  • Deck of Many Things- Drawing the Donjon or Skull cards seems to have no effect while in the Phlogiston, but they will take immediate effect upon entering a Crystal Sphere.
  • Robe of Stars- The wearer is unable to enter the Astral Plane.
  • Sending Stones- Messages have no chance of reaching a target on a different plane than you.
  • Staff of Power- There is no chance of traveling to a random plane of existence to avoid the damage from a Retributive Strike.
  • Staff of the Magi- There is no chance of traveling to a random plane of existence to avoid the damage from a Retributive Strike.

Art by Jim Holloway

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