AD&D 1E Atheist cleric situation...

[GMMichael]

the cleric draws his powers from "the universe" and not "the multiverse", then we could conclude his powers are of an unknown source that ostensibly exists somewhere in his own universe,

Nice take. I was thinking that worshiping the universe meant that its creator delivered one's powers, but I like this too.

In the 1e DMG it requires divine servants or the god to physically deliver spells 3rd level and higher.

So, scrolls only? I prefer my spells to be more potential energy than sub-light speed energy.

 

[Genghis Don]

I have a 10th level cleric in my campaign who doesn't worship any gods. He draws his powers from "the universe". As DM, I liked this spin on the class.

In my next game the players will need to travel through the ethereal plane. According to the Manual of the Planes, clerics are limited to only 1st & 2nd level spells if their deity doesn't make its home in the ethereal plane or an adjoining plane....but this cleric has no deity.

Should I let him slide & have access to all spells appropriate to his level or slap em with the limitation?

Well...there are NO atheist clerics in 1e; if they were a thing, they'd likely be limited to L1-2 spells always.

That said, you have been playing differently & like it, so super/special cleric they stay. I'd suggest the character would keep his powers in the inner planes, the ethereal, shadow & astral planes, as belief means nothing important in those planes. On the OUTER planes, however, belief is everything. I'd give the character 100% spell failure, a total inability to cast spells (successfully). Heck, I'd not let the character use cleric (only) magic items there either. EX: a mace +3 is fine, a rod of resurrection is out.
Use your standard magic alterations, though, so no protection from evil 10'r, dispel evil, insect plague, detect X always fails on ethereal targets, and so on.

I do have a much better overall suggestion though...simply toss the spell recovery limitations for everyone. The changes to spell effects are plenty. Keep the turning mods though. I'd also suggest some relaxation/2e-ification of "nature" spells...animals, plants, weather, etc, don't all need be so alien. The abyss can have plants or beasts, not just demons. maybe a penalty of some kind, but 1e TSR era folks FOOLISHLY ruined planar adventuring by trashing cleric/druid types so completely. Summoning magic is another area always TOTALLY nerfed, and for no good reason (they were almost always considered weak choices by players to begin with). I mean the stuff where you gets some wolves or orcs. Most players avoid the uncertainty plane travel brings like the worst sort of plague already, even without being rendered nigh or utterly useless.
edit: of the above examples, insect plague could be fine, with ethereal, prime or elemental bugs called.

 

[Tonguez]

That depends on you as the DM and the nature of the setting

1. You might argue that as he draws power from Universe he is restricted across the board when outside his native plane/Universe

2. You could go Plane by Plane - is the Planar nature such that he has full access or limitation

3. Allow him full access on all planes because Planar Multiverse = Universe

 

[Genghis Don]

How are you handling how he gets his powers normally? In the 1e DMG it requires divine servants or the god to physically deliver spells 3rd level and higher.

I dislike the 1e planar model of knocking out god connections for recharging cleric spells, reducing magical item efficacy each plane you cross over into (-1 plus per plane removed from its creation), and knocking out a bunch of spells on each plane. You could just ignore that MotP system entirely and treat it like later D&D where everybody gets their magic.

You could also go with the universe is all planes so he gets his powers from the ethereal as well and so full suite of spells.

Or you could go with universe is prime so count the prime as his god home plane so it is not on the prime but is adjoining.

Or you could go no deity so no deity in ethereal or adjoining so no recharge.

If you like the cosmology of a nontheistic mandate of heaven style cleric I say go with it.

AD&D 2e had nontheistic clerics of philosophies and forces and a similar planar type arrangement. Legends and Lore even has Taoist philosophy specialty priests IIRC. I don't recall how it handled those types of clerics in Planescape though.

reducing pluses of items & some messing with spells (but less than blanket crocking like Gary & the lads did) is what makes planar adventuring worthwhile, the final & eternal frontier of play. d20 on completely lost this key fact.
I agree on spell recovery/cleric/druids though (see post prior)

Loss of pluses is so important for home field advantage, that's one thing, but what it does in an accidental genius way is to RECREATE the hunt for cool gear for high level characters. For the first time, in likely some time, the characters NEED to hunt treasures hard, to improve AC, saving throws, combat, even combat to harm various monsters, again.
This can also be used to great effect for mid level characters; while this idea on came into fruition in 2e, it certainly can back jump to 1e, where a group of 6th to 8th level characters faces a completely different challenge up against a pack of werewolves on Gladsheim/Asgard than on the PMP.

Not only does plus loss make the hunt for magical goodies fresh, it also means those same goodies aren't any imbalance back at home! it's GENIUS for extended play indefinitely. It can also be handy for another visit to a given plane in the future, or not, as there are other planes to adventure on