I have had a very good chat with Iain about spirits. Thus, here it comes, edited only a little:
[Iain] On the subject of a spirit's "life points" determining what it can do. Rather than making the "life points" depend on the creature's steadiness or life skill it had when it was alive. You could make its "death points" depend a little bit on this, but more on it's knowledge and skills (as in other skills).
[manfred] (To ours interest is mainly, what it can do for us mortals, or what power it can give to us.) Yes, I was thinking of that... it's just how to bend it right is the question. But the "lending Skills" might have more potential in the end, I think. You can do more, but if you do not use the potential, it just vanishes.
[Iain] I agree - "lending skills" sounds good.
[manfred] Wizardly magic does the 'bang' and 'boom', but with this, you have to be active yourself.
[Iain] Regarding a shaman retaining it's own mana, perhaps he should only retain half (or some fraction of it); but perhaps the things he can do with it are different than when he was alive, some things being much easier (e.g. contacting spirits) but some things (materially affecting the real world) are harder.
[manfred] Also, spirits may not grow anymore in power, like the Living can.
[Iain] Could skill lending perhaps also help someone to develop their skills quicker?
[manfred] I think not implicitly...
[manfred] ...but if you do exceptional things (easier with higher Skills), you gain more Experience.
[Iain] Maybe not in power, but they should be able to gain in knowledge type skills.
[Iain] If only because they've been watching the world for a long time.
[manfred] And some of the EP can be devoted to that Skill only.
[Iain] That makes sense
[manfred] Ah, you mean the spirits!
[Iain] - Random idea - maybe spirits fade over time (very slowly; I'm taking over centuries or millenia) so the further back in time you want to contact a spirit, then only the most powerful would be around from that time.
[manfred] Perhaps, they can't advance in things too closely related to our world, since they are not a part of it anymore.
[Iain] That would seem sensible. They could perhaps advance in things related to the spirit world.
[Iain] The fading would make the communal ancestor spirits you suggested very potent: though any individual would have faded, the spirit as a whole continues.
[Iain] It keeps receiving "new blood" at the same rate at which it fades away (presuming the tribe remains at a constant size).
[manfred] Maybe not fade: http://www.strolen.com/forums/viewtopic.php?p=14035#14035
[Iain] Just read that - yes, that makes sense: they don't fade, they just lose interest in our world.
[manfred] Thanks, Iain! You have reminded me of that older thread... and it seems to fit.
[Iain] And the longer they've been dead, the more likely they are to have lost interest (unless, as you said), a shaman goes to persuade one to take an interest.
[Iain] This would also make a communal ancestor spirit less likely to lose interest than an individual one.
[manfred] Ah, MoonHunter's famous cookie metaphor...
[Iain] I don't think I've heard that?
[manfred] (that was about spirits liking "cookies"=attracting rituals, and why they would accept Wheel Magic)
[Iain] (Ah yes!)
[manfred] (and some spirits liking certain flavours of cookies... etc.)
[manfred] (Traditional Magic meant few excellent cookies. Wheel Magic would mean many okey cookies.)
[Iain] Oh - for mechanics of communal ancestor spirits, you could use your usual K10 triangular system. So, when 1 (not very special) person has died, the ancestor spirit is 1 unit (and is practically non-existent), 3 would make it 2 units; 5050 people would make it 100 units.
[manfred] Ahhh, good! I like the simple-yet-devious things you can do with linear progressions...
[Iain] Then a range of dead tribes people from 5000 to 125 000 (probably sufficient) gives a workable power-range for ancestor spirits of 100-500. (or divide by 100 and call it 1 to 5).
[manfred] Yeah, now just work out what one unit can do, what cannot, how to call it, how...
[manfred] ...and all the rest.
[manfred] Now, in my game world, spirits are "used" only in certain barbaric parts...
[manfred] (The usual northern plains+barbarian tribes. *sigh*)
[Iain] It works quite well if we extend it up to the God range. It's probably reasonable to say a major god has had around 50 million worshippers dying. This would give it a power rating of 100 (after dividing by 10). That seems about how much more powerful you would want it to be than an ancestor spirit of a tribe.
[Iain] And this "god" will definitely want to stick aroundm so priests can just worship him (as in the wheel magic thread).
[manfred] ...and I just wanted to ask myself why don't they worship some spirits too.
[Iain] Essentially, gods are just glorified ancestor spirits. This is actually going quite beyond your original concept, so you might well not want to use it.
[manfred] My gods are even more different... so no, but it is a very valid option.
[Iain] Saints and angels are kind of like spirits used within a big religion. Particularly saints. They're just not called spirits, but they could function mechanistically in the same way.
[manfred] So angels and gods are spirits that have been probably exceptional long ago...
[manfred] ...but have attracted and fused with other, similar spirits of believers, etc..
[manfred] So they have lost their unique identity to a degree.