Trying to run Spelljammer in 5e. Halp!

[Sayetsu]

I'm going to run an open-world, Spelljammer game in 5e. I bought the AD&D box pdfs on DMs' Guild, but I've noticed I'm in trouble with random encounters. I found tables on spelljammer.org, but they have a lot of monsters I seem unable to find conversions for, and heck if I know how to do it. Are there resources out there I can use? If I need to make my own tables, what should I put on them?

[SunderedWorldDM]

I'd recommend going through all the monster manuals and modules you have, writing down the names of every creature that says that it's found on another plane or from beyond the stars or whatnot, and then work to make your tables from there. You should have more than enough to work with, and can even start whittling it down depending on what you want in your campaign.

[Zarrgon]

Well, you are going to just have to make your own random encounter tables. You should have plenty of published monsters, plus all the converted and homebrew ones you can find online.

The huge bulk of the Spelljammer monsters have not been converted to 5E anywhere that I have seen.

[MaxWilson]

I'm going to run an open-world, Spelljammer game in 5e. I bought the AD&D box pdfs on DMs' Guild, but I've noticed I'm in trouble with random encounters. I found tables on spelljammer.org, but they have a lot of monsters I seem unable to find conversions for, and heck if I know how to do it. Are there resources out there I can use? If I need to make my own tables, what should I put on them?

What kind of difficulties are you running into? The exact statistics won't translate because 5E has a very different style than AD&D, but the concept should. E.g. a Flowfiend is like a four-armed troll that you need magic weapons to kill (and flies, and lives in space), so you could look at the 5E Troll stat block and just give it more claw attacks plus flight and weapon resistance or immunity. A Celestial Dragon is kind of like a much-tougher Gold Dragon with a force-based breath weapon attack, so use Gold Dragon stats but maybe bump everything up a notch (and make it a quarter of a mile long). A Stellar Dragon or a Constellant, well, 5E can't handle monsters that big, but they won't appear on your random encounter tables anyway.

Read the AD&D entry and them make up some 5E stats (and then use 5E DMG rules for assign a CR) and trust your judgment--your players will still enjoy it, really. Even if the 5E version of Dizantar or Scro winds up being different than the AD&D version, they won't care.

[Corsair14]

2e to 5e is fairly simple. I have run the original Ruins of Undermountain spur of the moment and converted as I went. Unlike the new version which wasn't out when I did it, the original had a bunch of core rooms pre-detailed and a huge expansive dungeon with only the map itself drawn in and no details. So pretty much you had to run it off the top of your head, like the teleporting skeletons in the room half filled with water. I gave the skeletons unlimited teleports to make it more challenging.

Basically triple the hit points.
AC converts pretty easy too. Subtract the AC from 10 and add it to ten. 2e AC 7 = 5e AC 13. 2e AC -2 = 5e AC 22.

As far as abilities, I prefer the lethality of 2e versus the hand holding of 5e so I convert them straight over from what the manual says. If its a lethal effect in 2e then its a lethal effect in 5e. You will have to use some judgement when it comes to which saving throw does what.

I also keep some of the original special effects of 2e which might not have carried over. For example skeletons halve damage from edged or piercing weapons but take double from blunt.

[Sayetsu]

Thanks, everyone!

[Throne12]

Ya read other comments after responding they say what I would but better.

[Monster Manuel]

As for the monsters, you've got the beholders and mind flayers in the DMG, neogi in Volo's, and the giff in mordenkeinen's. Clockwork horrors are in there somewhere, too. Many of the iconic spelljammer monsters are already accounted for, and I've done OK with just re-skinning something basic for the outliers, and tacking on a few spell-like abilities.

For instance, to get the Arcane, I just took a half-ogre and dropped its strength and gave it an int of 18, plus invisibility and dimension door. It wasn't perfect, but got the idea across.

Scro were just orcs from volo's, with npc templates attached.

Another thing I did was to change up how spelljamming helms worked...instead of using up spell slots to power it, it just used your Concentration. More fun for the pilot, but still meeting the original intent (while you're powering the helm, your casting is impeded).

Good luck, it's a fun setting!

[MaxWilson]

Another thing I did was to change up how spellhamming helms worked...instead of using up spell slots to power it, it just used your Concentration. More fun for the pilot, but still meeting the original intent (while you're powering the helm, your casting is impeded).

Very elegant!

[Monster Manuel]

Very elegant!

Thanks!

Also, I'm kind of glad you quoted me before I caught my typo. "Spellhamming" has a great pigs-in-space vibe to it, and I was a little sad to fix it in my initial post...

[Laserlight]

"Spellhamming" has a great pigs-in-space vibe to it...

Turns out Mjolnir was Thor's war boar, eh?
And "pig iron" is a thing.
I'd better stop.