ToME WikiDescribe IdeaArchive/AngryGod here.
It seems to me that players abuse gods, and they should get angry. I reffer especialy to the situation when the God abandon you. I mean, I worship Meklor and I know He will be angry at me if I destroy the ring, but I destroy it, Meklor just abandon me and at the first temple I see... puff, I am again a dark worshiper. It just is not the god's nature. I think He would at lest lay a nice Morgothian curse on me (reflected on all/some of my equipment) or summon some balrogs to teach me a lesson. Also, Manwe have sent powerful mages to fight angainst sauron and will just leave me, one of his followers, if, after finding the ring I decide to wear it? No, He will probably send some thunderlords against me. And so on, I think a punishment is in order for making each god abandon you.
NeilStevens: Are you sure you can still re-follow a Vala after being abandoned in 2.3?
ZasVid: Yes, in case of Melkor at least. Nothing prevents his Altars from appearing in dungeons after you destroy the Ring. I can't comment on other Valar, as none of my characters recently wore the One in Lothlorien.
NeilStevens: But have you tried using the altars? It's not enough to have seen them.
On to the idea: well, Melkor sends tons and tons of his minions after you anyway, so why should he send more? Well, actually he probably would send more, but then, why couldn't he summon things at a powerful good adventurer coming for him through Angband? No, I don't want to think about groups of undeads, demons and dragons randomly appearing out of thin air once you hit high levels.
Other Valar are a different case. They pledged that they won't take active part in dealings of the Middle-Earth, so all they can do is give some far-reaching care to a pious worshipper, but active intervention to counteract his deeds? They didn't do a thing (except asking Eru for help) when Ar-Pharazon turned evil and attacked Valinor, so why would they do anything against someone who didn't even take action against them?
Hoom... I've gone on a rhetorical questions' spree here. Weird.
RavenRed: Another answer is to create a "placeholder" god like "Foresworn" which prevents you from picking up another God AND has an intrinsic penalty like aggravate or XP drain. (both of which are relatively trivial once you've reached the stage where they abandon you)... if you were feeling really keen you could create different ones for each God with different, thematically appropriate (Yavanna summons hostile Ents, etc) penalties...
NerdanelVampire: Aggravate is a flag that can be far from trivial. It will just totally kill any character concept based on stealth or pets. Summoners will be prevented using their main offense. I love stealth and hate aggravate.
RavenRed: Then the answer is obvious, don't wear The One...
It's the same disadvantage as the Troll Blood corruption, but far later in the game. And as Neil is wont to point out, there's no such thing as an involuntary corruption. Seiously, though, I agree that it CAN be a game-ender. It was only an example of how awesomely destructive abandoning your Valar SHOULD be...
ChrisAmes: All gods should abandon you if your piety gets too low, but with no penalties. If you have been abandoned by a god you should not be able to worship that god again, but if it was Melkor you should be able to worship the others or vice versa.
NerdanelVampire: This idea (posted on this page because of similarities) is what I want to do in my module but I decided put it here in case other people are interested. I don't think the idea will ever end up in ToME though.
You can abandon your god if you convert on the altar of another god and your god abandons you if your piety gets very negative. In either case, a counter is started. If you find the altar of your god before the counter reaches zero, you are fine. You beg for forgiveness and your god takes you back. (However, another god may now get angry at you...) If the counter runs out, your god does to you something nasty but not immediately lethal. The exact nature of the punishment depends on the god.
You can also sell your soul. (Good gods would probably call this something like the Holy Oath of Dedication.) Selling your soul has immediate benefits, possibly one of your choosing from a list in the manner of the standard Faustian bargain, but you will never be able to abandon your god. If you get into a situation where your god would abandon you, (s)she won't, but (s)he will punish you periodically anyway until you get back to his/her good graces or die.
Zonk: Gods should probably be handled in a somewhat more flexible way - one thing I had been thinking, when considering doing an 'Age of Mythology'module, is that we could allow the player to have different piety/grace values related to different gods. Of course, for example, if you worship Melklor all other gods will dislike you - however, there shouldn't be problem if you wanted to worship both Eru and Aule, altough perhaps you would have less piety with each of them than would an individual worshiper...just an idea. Oh, and the 'selling your soul'idea is wonderful.
Ingeborg Norden: Zonk has a valid point, especially for gameworlds with genuine polytheistic religions. Norseband, if you'll forgive a module plug, should allow characters to serve more than one god in the same pantheon: even someone who's fervently attached to Thor won't automatically hate or snub the rest of the Æsir. (Characters in a monotheistic faith, on the other hand, would get into biiig trouble for trying to court another god's favor....)
I'd propose reserving the "foresworn" status only for major actions (like wearing the One in standard ToME) that alienate most of a pantheon. For lesser actions, divine punishments might strike when the character goes below a specific piety level; reaching a new low when the god is already angry would make the consequences worse.