That will do for a name. It means “underground”, it refers to the planet as Ecumenopolis-Necropolis and it has the cod-classical feel that suits Warhammer 40,000's grimdark.
Welcome to Planet Hypogeum Prime in the Hypogeum star system. When there was still such a thing as the Imperium of Man, Imperial astronomers and cartographers knew it as Star 0-935696-21-0. (A free lollipop to anyone that gets that reference).
Character Classes & Races.
I'm currently toying with just three. The setting is humanocentric so obviously we will allow Fighting Men, Clerics and Magic-Users. I'm thinking that Clerics will generally follow a much degraded and corrupted form of the Emperor as Omnissiah but it's important to remember that nobody on Hypogeum has any inkling of their being life outside of their planet other than in half-forgotten tales of being brought to Hypogeum from “somewhere else” during a great Sky War.
I'm also allowing Elves, but in this setting they are renamed Eldar. 40K has a whole sub-sect of Space Elves, those who turned their back on the increasingly degenerate Eldar civilization pre-fall and went to virgin worlds to become, essentially, Space Amish. If these have ended up on Hypogeum then they fulfill the Elf role.
Eldar PCs are renegades and outcasts from Eldar society, perhaps criminals. Eldar society as a whole is not overly friendly to Humanity, the full-on nasty, spiteful Elf archetype.
I want to add another “weird” race, outside of the usual Elf/Dwarf/Halfling triumvarite. Through a strictly scientific method (random thumbing through the books in the xD&D library) I found out the Fiend Folio entry for the Dakon. Dakons are intelligent, LN-aligned gorillas that speak the Common tongue. I envisage them as “noble savages”, clad in primitive jewellery and with dyed fur and ritual warpaint. They can be Fighting Men or Clerics (as tribal shaman) and while they can't wear armour, they do get a natural AC of 5 and a bare hand attack that does d6 (d10 in the original AD&D but I've downgraded it to match the power curve of the D6-for-all-damage oD&D). I might prohibit them from using human weaponry in which case they will get the +2 to hit from Fiend Folio.
Dakon (as NPC) - AC:5, HD:1+1, Attacks:Bare hands (1d6), Move:6, HDE/XP:1/15
Dakons attack at +2. Exceptional individuals may have levels in Fighting Man or Cleric classes.
Creatures of Chaos
The WFRP world has one of the best excuses ever written for nonsensical monsters that don't fit in with any known ecology – The Incursions of Chaos. Put as simply and as briefly as possible, the Warhammer World was once the home of an impossibly advanced, space-faring race which might have been the amphibian “Slann” race, but were certainly the Old Ones that the Necrons warred against. They had great warpgates at the poles of the planet for cosmic travel, after the great cosmic catastrophe they burst open and keep showering the world with warpdust, the solidified form of raw chaos and akin to radioactive fallout. Many weird and impossible beasts either enter the world through these gates or are produced by the mutating effects of warpdust upon the native fauna. So any nonsense in WFRP can be justified with the old “A Wizard Did It” piece of inspired hand-waving, only this time it's “Chaos Did It”.
(Interestingly back when 40K was released, the background was intended to be the far future of the Warhammer World. This extract from WD93's launch special on Rogue Trader proves it.
This seemed to be ignored and/or retconned in later 40K writing but it's such a stonkingly good idea that I've always remained loyal to it. Doubly interesting is the fact that the backstory of the Necrons fits in with this “fantasy future” idea perfectly with the original psychic tsunami of the creation of Slaanesh being the disaster that split open the warp gates on the Warhammer World. With Orcs/Orks, Elves/Eldar and Humans being warrior races created by the Old Ones to war against the Necrons we can see that the Warhammer World simply became Terra of the year 40,000.
Suffice to say this interpretation is “in” for Hypogeum. Neat that this new oD&D world is set in the impossibly far future of the games of WFRP we loved in the past).
Back to Creatures of Chaos. The fact that the entire centre of the world is a bloody big rent in the fabric of time/space letting raw chaos leech out gives me the excuse to use every nonsense Fiend Folio creature and the weird random stuff that Age of Fable's random dungeon and creature creator comes up with.
A Wizard Chaos Did It.
I've never used them in the past, but for me “Lawful” and “Chaotic” are wonderful words redolent of my early experiences in the RPG world. Like “Wandering Monsters”, “Cleric” (I never, ever went over to the 2E aberration “Priest”), “Fighter” (likewise – never “Warrior”) and “Dungeonmaster” these are words that are so tied to D&D in my mind that I can never imagine going without them. (I'm odd like that – in 40K I insist on Imperial Army, not Imperial Guard).
I'm tempted to use an alignment scale of Good-Neutral-Evil to determine an individuals general outlook on a strictly humanocentric scale. Totally outside of this axis is “Chaotic”. This is irrelevant to whichever coloured hat the cowboy is wearing and exists to mark a creature as being strongly tied by nature to the element of Chaos. All Chaos Creatures are Chaotic and so are Eldar – they are flighty and unpredictable and it was a personification of their nature that became the Chaotic power Slaanesh.
And of course because I like the word.