Another staple of the Elric stories that I'm particularly fond of is the concept of many and varied planes of existence. This concept goes to the heart of the Eternal Champion stories. The planes take many shapes and forms. These were no doubt the inspiration of the inner and outer planes of ADnD.
First there are the elemental planes, inhabited by the four classical types of elements: earth, wind, fire and water. Elric visits these on occasion and summons elemental minions to do his bidding from these planes throughout the saga. The elemental planes are 'close' to some planes and 'further' from others. There appears to be no set hierarchy as to the organization and location of these elemental planes. Passage to and from these elemental planes happens most frequently through the corresponding Earthly element (travel through the sea to get to the plane of water, etc.).
The next most common type of plane is that of alternate timelines. The Eternal Champion exists in all the various versions of Earth; each one of these versions is a distinct plane that can be traveled to. Sister to this type of plane is the concept of time as a plane. This provides the possibility of travelling to the past or the future not only within one's own plane but other planes as well.
Then there are all the various realms of Limbo and discarded dimensions inhabited by all manner of men, beasts and demons. The possibilities seem limited only by the writer's imagination. Again, no order or pattern can be discerned. The relationship between each plane is unique as are the properties covering the physical and magical laws of a plane.
There is one last type of plane in these stories, the eternal city of Tanelorn. This city exists in all planes throughout time. It is the final quest of many heroes seeking rest from their adventures. This could be viewed as a mobile plane of sorts, it's location within a given plane may be static (beyond the Weeping Wastes), but it may not always be accessible. From within the city it may appear that inhabitants can exit the city to visit a variety of planes depending on where they happen to be 'anchored' at the moment. This last one is a favorite of mine because it matches thematically with one of my favorite comic book settings: K'un L'un, the birth place of Iron Fist.
Looking at SnW White Box I see that there is no spell for travelling between planes; this is as it should be. SnW has its feet firmly planted in the Old School Renaissance which holds that the adventurers should be heroic, but not superheroic. Heroes who can plane-hop at will is the stuff of comic books. Adventurers of the OSR do travel to other planes, but I see these trips are accidental or arranged by some powerful entity; they are not the stuff of everyday fare.
So this begs the question of how the PCs will be able to access these planes. First there needs to be natural conduits to various planes closely associated to the prime plane of the PCs. This could be a deep sea tunnel that leads to the elemental plane of water, a dark dungeon cavern leading to the elemental plane of earth, and so forth. Also natural conduits should exist to different times and alternate worlds. The most common means of this in the Elric stories is becoming lost at sea; the Seas of Fate bridge worlds and times.
Another means of access would be through powerful entities or agencies. Demons, elementals and beast lords may be able to provide access to various planes. Agents of a particular power may have a magical device that allows passage through the planes - again, the black ship that sails the Seas of Fate is a good example of this variety.
Spells that access various planes are not out of the question, but I would like to limit this as much as possible. Certain planes may be more accessible through spells than others, or may only be accessible at certain times or only through great sacrifice. This will remain to be seen as development progresses.
Finally the eternal city brings an interesting possibility to the mix. Since this city can theoretically be any 'where' and any 'when' it provides the possibility of players creating any imaginable character as well as a way of accessing many planes. There was a time that this would have really bugged me when preparing a campaign. The concept is too big for most games, I didn't want to have Jedi running around in my quasi-medieval world. But now, with a few more years under my belt, I'm not so sure that it bugs me. One final benefit of the eternal city, it provides me with a way of explaining why there would be a monk in a quasi-medieval setting.
Adventurers-from-other-worlds has a solid foundation in fantasy literature: the D&D players in Quag Keep, Holger Carlsen in Three Hears, Three Lions, John Carter Warlord of Mars. Murlynd, one of the hero-gods of Greyhawk is clearly from Earth's wild west. So I'm in good company here.
The Deities & Demigods books of ADnD was the first to put a basic form and order to the inner and outer planes. These concepts were later formalized in the Manual of the Planes. Both of these are fine works, but I feel they are too rigid for Icosa. I may be borrowing some concepts - elemental, etheral and astral planes - but I think I'll keep things loose and flexible. This will let me handle things on a case by case basis. This may need more firming up when giving more depth to the Contact Other Plane spell.
Next time around I'll be looking at the battle between Law and Chaos.
Follow Your Bliss,