My players are 2  level 7 gunslingers/artificers, and they are on my homebrew world, they are about to come across a massive spelljammer ship buried in a desert lake temple surrounded by a troll city(think Warcraft trolls). Now I love this idea of this turning into a spell jammer campaign, especially with the massive ship being a mindflayer dreadnaught(and it very much being not empty). Them either getting kidnapped and dragged into space or trying to steal it.

I’ve never run a spell jammer campaign before, so I need ideas for places to visit, monsters, factions for them to face and a highly dangerous bbeg.

Its a homebrew setting so feel free to be creative.

N'ghathrod, the mind flayer pirate always jumps to mind for Spelljammer BBEGs. He exists in 5e lore here.

Borg modrons?

Great idea!

Hell yeah!

Neogi's were one of the classic villains of the spelljammer universe. Have it be a lost Neogi scout ship (mindspider), maybe with an egg present waiting for a source of heat to come near it to become enslaved and take it to a hive or maybe it was Neogi Master mummified who fled because he didn't want to be devoured for preproduction.  They are truly the scum of the crystal spheres. 

My suggestion, treat yourself and buy the original boxed set for spelljammer.  It'll cost you $90 on eBay, and you'll get a ton of setting information, monsters, ships and factions that are available.    Look up SpellJammer Adventures in Space Box Set.  It was a lot less two years ago when I went deep into Spelljammer lore and started collecting all the source books I could find.  You get a true wealth of materials.  What WotC puts out today is a pathetic joke compared to older editions.  Three large poster maps, one of Rock of Bral, space combat and the actual true SpellJammer itself (its massive), two books one of lore and one for rules, tokens for combat play there are a lot of little cut out ships and the nice one is the card stock ships in full color with stats and on the back with grids.  Man its just such a nice package overall.

This is an ebay that shows you what we got in the boxed set:  https://www.ebay.com/itm/185397537665?hash=item2b2a8deb81:g:CjgAAOSwvmpiZBMf

If you want the miniature ships from Wizkids for space combat it will cost you, $15 a ship and they are tiny.  Not happy with that one at all.

Quote from Portential >>

Neogi's were one of the classic villains of the spelljammer universe. Have it be a lost Neogi scout ship (mindspider), maybe with an egg present waiting for a source of heat to come near it to become enslaved and take it to a hive or maybe it was Neogi Master mummified who fled because he didn't want to be devoured for preproduction.  They are truly the scum of the crystal spheres. 

My suggestion, treat yourself and buy the original boxed set for spelljammer.  It'll cost you $90 on eBay, and you'll get a ton of setting information, monsters, ships and factions that are available.    Look up SpellJammer Adventures in Space Box Set.  It was a lot less two years ago when I went deep into Spelljammer lore and started collecting all the source books I could find.  You get a true wealth of materials.  What WotC puts out today is a pathetic joke compared to older editions.  Three large poster maps, one of Rock of Bral, space combat and the actual true SpellJammer itself (its massive), two books one of lore and one for rules, tokens for combat play there are a lot of little cut out ships and the nice one is the card stock ships in full color with stats and on the back with grids.  Man its just such a nice package overall.

This is an ebay that shows you what we got in the boxed set:  https://www.ebay.com/itm/185397537665?hash=item2b2a8deb81:g:CjgAAOSwvmpiZBMf

If you want the miniature ships from Wizkids for space combat it will cost you, $15 a ship and they are tiny.  Not happy with that one at all.

 If you aren't married the physical, that $90 box set costs $10 on Drivethru RPG.

Quote from Verenti >>

Quote from Portential >>

Neogi's were one of the classic villains of the spelljammer universe. Have it be a lost Neogi scout ship (mindspider), maybe with an egg present waiting for a source of heat to come near it to become enslaved and take it to a hive or maybe it was Neogi Master mummified who fled because he didn't want to be devoured for preproduction.  They are truly the scum of the crystal spheres. 

My suggestion, treat yourself and buy the original boxed set for spelljammer.  It'll cost you $90 on eBay, and you'll get a ton of setting information, monsters, ships and factions that are available.    Look up SpellJammer Adventures in Space Box Set.  It was a lot less two years ago when I went deep into Spelljammer lore and started collecting all the source books I could find.  You get a true wealth of materials.  What WotC puts out today is a pathetic joke compared to older editions.  Three large poster maps, one of Rock of Bral, space combat and the actual true SpellJammer itself (its massive), two books one of lore and one for rules, tokens for combat play there are a lot of little cut out ships and the nice one is the card stock ships in full color with stats and on the back with grids.  Man its just such a nice package overall.

This is an ebay that shows you what we got in the boxed set:  https://www.ebay.com/itm/185397537665?hash=item2b2a8deb81:g:CjgAAOSwvmpiZBMf

If you want the miniature ships from Wizkids for space combat it will cost you, $15 a ship and they are tiny.  Not happy with that one at all.

 If you aren't married the physical, that $90 box set costs $10 on Drivethru RPG.

 No maps, no tokens, no card stock hand outs.  Its a trade off for how you want to play it.  The digital version ain't exactly great either for scans.

I was never impressed with the 2e ship-to-ship combat game.  For my upcoming family game I’m going to teach the older kids XWing and just carry the results from one game into the other.

Quote from Portential >>

Quote from Verenti >>

Quote from Portential >>

Neogi's were one of the classic villains of the spelljammer universe. Have it be a lost Neogi scout ship (mindspider), maybe with an egg present waiting for a source of heat to come near it to become enslaved and take it to a hive or maybe it was Neogi Master mummified who fled because he didn't want to be devoured for preproduction.  They are truly the scum of the crystal spheres. 

My suggestion, treat yourself and buy the original boxed set for spelljammer.  It'll cost you $90 on eBay, and you'll get a ton of setting information, monsters, ships and factions that are available.    Look up SpellJammer Adventures in Space Box Set.  It was a lot less two years ago when I went deep into Spelljammer lore and started collecting all the source books I could find.  You get a true wealth of materials.  What WotC puts out today is a pathetic joke compared to older editions.  Three large poster maps, one of Rock of Bral, space combat and the actual true SpellJammer itself (its massive), two books one of lore and one for rules, tokens for combat play there are a lot of little cut out ships and the nice one is the card stock ships in full color with stats and on the back with grids.  Man its just such a nice package overall.

This is an ebay that shows you what we got in the boxed set:  https://www.ebay.com/itm/185397537665?hash=item2b2a8deb81:g:CjgAAOSwvmpiZBMf

If you want the miniature ships from Wizkids for space combat it will cost you, $15 a ship and they are tiny.  Not happy with that one at all.

 If you aren't married the physical, that $90 box set costs $10 on Drivethru RPG.

 No maps, no tokens, no card stock hand outs.  Its a trade off for how you want to play it.  The digital version ain't exactly great either for scans.

 Sure, but a rudimentary search on Google will find content you can get printed on card stock at a local print shop for a few dollars. Which, if they play online, won't cost him anything to bring into a VTT.

This is probably outside the scope of what you want to do OP, but I personally am tempted to mash Ravenloft into Spelljammer and reflavor the Darklords as beings similar to the Goa'uld from Stargate.  😁

Quote from Heartofjuyomk2 >>

N'ghathrod, the mind flayer pirate always jumps to mind for Spelljammer BBEGs. He exists in 5e lore here.

You could also just use a regular mind flayer as well as a monster.

okay, so, here me out.... space hippos. i don't know much about spelljammer, but giff have been one of my favorite monsters in dnd 5e, and i have an idea:

so, lets say they manage to get the ship working or something, then why not have a faction from spelljammer REALLLY want that ship because there is something special about it, so they hire a group of Giff pirates to hunt the party down, and for a giff captain you could use a beholder and flavor the rays as special magic firearms.

Quote from the_minmaxed_druid >>

okay, so, here me out.... space hippos. i don't know much about spelljammer, but giff have been one of my favorite monsters in dnd 5e, and i have an idea:

so, lets say they manage to get the ship working or something, then why not have a faction from spelljammer REALLLY want that ship because there is something special about it, so they hire a group of Giff pirates to hunt the party down, and for a giff captain you could use a beholder and flavor the rays as special magic firearms.

 That actually does sound like a cool idea, the problem would be if OP's players want everything to be serious.

Quote from BoringBard >>

Quote from the_minmaxed_druid >>

okay, so, here me out.... space hippos. i don't know much about spelljammer, but giff have been one of my favorite monsters in dnd 5e, and i have an idea:

so, lets say they manage to get the ship working or something, then why not have a faction from spelljammer REALLLY want that ship because there is something special about it, so they hire a group of Giff pirates to hunt the party down, and for a giff captain you could use a beholder and flavor the rays as special magic firearms.

 That actually does sound like a cool idea, the problem would be if OP's players want everything to be serious.

 Giff are some of the most serious things in dnd. Don’t mess w them!!

yeah! these waterpark space horses will stuff you in a barrel of lit gunpowder while stealing your collection of monsters that can beat giff in a fight! its a pretty small collection tho.

Thank you for all these great ideas! How do you handle space battles?

I know we all love the giff (or at least we should, look at them!) but I think a Giff Empire would be great villains. Coming into a familiar port, players might find eventually a Giff flag planted there and a LOT of guns pointed their way. They would act as this colonizing force gradually siezing territory across the Astral Sea with little regard for who'd had any claim before them, all for the glory of the Empire of course! Might be a bit on the nose what with their real world inspiration, but hey, it works as an antagonist. 

The Empire wouldn't even need to be the main antagonist either. They could be a persistent annoyance as players find their favorite watering holes suddenly subject to the Empire's laws and taxes, resources being drained and sent back to "civilization" sparking a need for some heroing on the part of the players. 

YEEESSSS!!!!

The East Interstellar Trading Company colonizing and civilizing all you barbarians in the Outer Rim.  Yeah, they'd be great antagonists.  

God, to give Ralph McQuarrie a couple million bucks and tell him to design The Raj In Space!  That would look so sick!  I am so tempted to overhaul my whole space campaign...

HOLDON. ANOTHER IDEA. okay, so this might not fit as well as space hippos, but it could pair up with it. so, along with space hippos, a Loxodon Mafia.