Populating Jupiter-sized planet (maybe its moons, too)?

[Schattenbach]

I'm currently working out some Jupiter-sized planet ... the planet is meant for Etrian Odyssey style exploration in particular, as far as the plot is concerned thus far, and thus its better if there isn't anything over the top ... weird ... running around on it.

# Some very general details about the planet itself ...

The atmosphere and such is pretty enormous (compared to what's commonly the case on earth-like planets) and otherwise, while there are some minor differences overall (due to some local conditions that make the air in those areas toxic) but as the upper parts are much less dense overall, the air pressure is usually not that much of an issue, too.

The solid parts of the planet are jupiter-sized (so overall, the planet is actually significantly larger than Jupiter) in terms of surface area, the gravity is, due to magical anomalies, mostly the same as it would be on earth, maybe slightly higher, though there are also some regions on the surface (as well as within several regions found underground) where the gravity is much stronger (more along the lines of what one would normaly expect from this kind of planet size).

Around 80 percent of the planet's surface are covered by water (90 percent being salt water in the form of oceans, lagunes, ecetera). ~40 percent of the water covering the surface isn't all that deep (i.e. at most twenty metres), though, and the deeper parts (i.e. more than 1,000 metres deep) only make up around 20 percent or so ... and even among these 20 percent, only around 30 percent go down below 4,000 metres (to up to 90,000 metres in at least some cases).

# some general details about how developed the planet is thus far ...

Over the course of the last several millions of years, there have been several high-magic empires (some similiar to those found in Eberron and such ... most of them elvish in nature) or otherwise quite advanced societies (some of them made it up to progress level 5) but pretty much all of them either collapsed on their own or due to war ... or they were destroyed by dragons, by damaging nature too much and angering the planet that made them suffer quite a bit as result, by developing to much and angering the gods that control the planet (who thus made an example out of them to keep everything under their control), by angering the planets main dragon deity and being smashed to pretty much nothing, by being destroyed as side effect of the regular conflicts between the giants (and Titans) and the dragons (until the giants pretty much lost an were mostly wiped out from the Planet), by getting involved in the conflicts between nonevil and evil dragons, by some demonic invasion (until that demonic invasion was stomped by the dragons ... they never had much of an chance), by some natural disaster, ecetera ... the list goes on. So there are plenty of ruins that can be found on the planet, but as far as dominant high magic empires go, there aren't any at the moment, though some of the currently existing societies are experiencing some serious magitech-boom at the moment.

The most dominant group on the planet is dragons and they're really everywhere in some shape and form, though in at least some areas, they're being forced back by some particular outstanding monsters. There's actually a bunch of Quasi-Deities, Demigods and Lesser Deities running around on the planet ... few minor plant/fey/magical beast, ecetera deities that act as regional protectors (like some divine trees and such) ... a bunch of Quasi-Deity Dragons with some class levels & their twelve Dragon Ascendant levels ... a bunch of other lesser deities and demigods that act as local gods ... so for areas under their protection, things are quite a bit easier.

# Significant native Tribe Types (in no particular order):

Elves (various, though some of them have already been destroyed over the course of the last two thousand years; Wood elves and such still do just fine, Grey Elves and such also managed to hang on, Aquatic Elves couldn't keep up with the vicious creatures populating the oceans and were completely wiped out)
Gnomes
Half-Orcs
Humans (mostly wiped out since their last blunder from a while ago, but a few million are still around)
Lizardfolk (various)
Orcs (various)
Goblinoids (various)
Trolls (various)
Ogres
Onis
Ocean Giants (the only dominant giant species that's currently found on the planet)
Storm Giants (have already been destroyed long ago)
Sand Giants (have already been destroyed long ago)
Hill Giants
Stone Giants (have already been destroyed long ago)
Forest Giants
Sun Giants (have already been destroyed)
Firebolgs (have suffered quite a bit of damage and are currently facing decline)
Half-Orcs
Midgard Dwarves
Grey Dwarves/Duregars
Other dwarfes (have already been destroyed long ago)
Halflings (have already been destroyed long ago)
Various Fey races and such (Sirenes, Nymphes, Dryades, Nereids, Petals, Pixies, Siabries, Nixies, Oreads, Satyrs as well as various other commonly Fey do perfectly fine and actually make up the second most important group next to the Dragons)
Half-Elves
Fomorians
Mountain Giants
Loxos
Centaures
Myconids
Gnolls
Ormyrr
Harpies
Merfolk
Lamias
Kobolds
Ibixians
Rakashas
Sahuagin
Some other sufficiently humanoid creatures (monstrous humanoids and magical beasts in particular)

As far as particular outstanding (i.e. powerful) monsters go, the ones I think might go well with this setting (and that are powerful enough to dominate at least some regions) and would make decent FOEs (http://etrian.wikia.com/wiki/FOE) for characters between level 15 to up to 30 to face (and to run away from if necessary) ...

FOEs (in no particular order) ...

Lots and lots of dragons, and starting with Ancient Dragons, they're actually being strong enough to be bosses in plenty of areas
Landwyrms
Other Dragon-types of particulary large natural bulk and strength, like Linnorms
Particulary high advanced Dragon Turtles or Dragon Eels or Sea Drakes
Brachyruruses (those large primordial wolf-like magical beasts)
Chaos Rocs
Tayellahs (those three-headed panther like things from the epic level handbook)
Ruin Swarms (that slightly nasty pseudo-ooze-like swarm from the epic level handbook)
Vermiurges (those scorpion-like Aberrations from the epic level handbook with that vermin swarm effect around them)
Sirrushes (those one or three-headed lizard-like magical beasts)
Prismasauruses
Bone Oozes (there are a lot of those underground as most creatures don't want to face of against them there)
Flesh Jellies (there are a lot of those all around the planet as plenty of dragons don't want to deal with them)
Particulary powerful Mu Spores
Some particulary far advanced dinos like Seismosauruses, Allosauruses or Spinosauruses
Some particulary far advanced Dire Animals (like Dire Elks, Dire Wolves, Dire Tigers, Dire Bears or Dire Elephants) or other particulary far
advanced prehistoric or pseudo-prehistoric creatures like Megadolons or Mastodons or Grizzly Mastodons
Some particulary far advanced elemental-based beasts like the Frost Salamander
Megapedes
Particulary powerful Nightmare Beasts
Particulary powerful Orcworths
Thorciasids (those oversized parasitic cockroaches)
Devastation beetles as well as web-spinning Devastation spiders
Spirits of the Land (if angered)
Elder Treants (if angered)
Ancient Night Twists or particulary powerful Night Twists
Cloud Rays
Behemoth Eagle
Behemoth Gorilla
Brood Keepers
Particulary powerful Oaken Defenders
Particulary powerful Siege Beetles
Leviathans
Soarwhales (only when in significant numbers, though)

Particulary powerful Krakens
Particulary powerful feys in general
Phoenixes
Garngraths
Genius Locis
Ha-Nagas
Vermin Lords
Gibbering Orbs
Teratomprphs
Fiendwurms
Phaethons
Hecatoncheires
Xixecals
Chichimecs

Particulary powerful Hill Giants
Particulary powerful Cyclopse-Type creatures/Greater Cyclopse-Type creatures
Geriviars
Ocean Giants (only as Tribe, though)
Mountain Giants

...


Some suggestions about what to do with the wildlife (that's mostly made up of the not-so-weird animals, magical beasts, oozes, plants, ecetera) for particular regions (high in the sky, underground and for the sea in particular), what powerful monsters in particular would fit in nicely in that setting and such as well as other suggestions that might help in improving the planet's flora and fauna would be nice.

[WbtE]

Working with over a hundred times the surface area of earth, I'd think that you could throw the kitchen sink at it. Rather than relatively uniform flora and fauna, have radically different biomes (especially on the islands). You could pull out the old cliche of silicon-based lifeforms, have an island almost exclusively inhabited by automatons (including mechanical animals and plants), etc.

From the description, I don't think that you'd get anything very interesting high in the sky unless there's anomalies to make the low air pressure and low temperature survivable. But again, with this scale and arcane history anomalies must crop up so floating castles or what-have-you are certainly possible.

[Nifft]

A planet like Jupiter, with a surface?

Not sure how that could work.

I've done a Jupiter-oid planet where people lived on balloon-plants, which floated in the landless winds, their long root-tendrils drifting through the Poison Deeps for carbon & sulfur, their great leaves catching precious rain-water from the Cold Heavens. Basically, it was an equatorial band of oxygen & nitrogen, close enough to the surface to catch the water of a wide ice ring in a decaying orbit.

You could see the boundary of the Poison Deeps, but it was just a different color of cloud. Obviously you can't breathe down there.

If you go too far north or south, the rains stop, and your only company would be some dry & dying balloon-plants. If you could go far enough, you would encounter a different kind of poison clouds.

Sometimes, a horrible Aberration emerges from the Deeps, and must be slain.

Metal artifacts are rarer than metal on Athas, and give some hints as to how humans came to live in this strange place.

[dhasenan]

A planet like Jupiter, with a surface?

Not sure how that could work.

A crust of, say, one mile deep, suspended on a gas giant with magic, constructed by an unknown deity with divine rank 20+ as a weekend project.

But yeah, this thing is huge. If you have a population density like modern Earth, you will have 280 billion inhabitants. You could have a wild magic zone a thousand miles in diameter and it'd only impact 0.1% of the planet. You can do anything you want and not really worry about keeping things consistent.

[Epic Legand]

1,300 earths fit in one Juptier. Read Ringworld for some ideas on scale. With that level of scale, you could have 5,000 subraces of elf alone, and it would work. The real answer is that you will never play enough in this world to explore more then .001% of it. At a certain point, to much diversity means you have zero expectations. How can players learn about a particular race or culture when I gets lost among millions of other ones?
Pick 5 areas you want to explore with the players, and then keep your setting, you only need those 5 areas, because your players could travel their whole lives, and still not get outside that small area. You still keep your backdrop...but you don't need to develop millions of other races/monsters or cultures. You can still have whatever you want pop out, explained as "from WAY over there". Maybe limit some types of magic to certin parts for start. Psionics comes from one area, Wizardry from another, POW skills taught from the east ect.