As a DM or setting designer; what could you create, within this premise?

Perhaps Magic isn't as common as it used to be?

Perhaps Magic isn't as powerful as it used to be?

Perhaps Magic isn't as predictable as it used to be?

Perhaps Magic has been Lost to Time?

Quote from: Razor 007;1144487As a DM or setting designer; what could you create, within this premise?

Perhaps Magic isn't as common as it used to be?

Perhaps Magic isn't as powerful as it used to be?

Perhaps Magic isn't as predictable as it used to be?

Perhaps Magic has been Lost to Time?

Magic is no longer safe to use. The use of magic is inevitably corrupting to the user, physically, mentally, and spiritually.

Quote from: RandyB;1144508Magic is no longer safe to use. The use of magic is inevitably corrupting to the user, physically, mentally, and spiritually.

Earthdawn featured magic that was drawn from the Astral. Unfortunately,  the Astral had become polluted so that drawing energy from it was increasingly dangerous without using a "spell matrix" (a sort of filter set for a particular spell) and there were predatory Horrors within the Astral too. Earthdawn could be played as high fantasy, but it was intended to be darker horror fantasy.

My own magic system works through the manipulation of daemons trapped in vessels with magical seals. The art of manipulating those daemons is still passed from one wizard to the next, but the means of conjuring those daemons and trapping them in the first place has been lost to time.

The Stardust movie depicted that use of magic required life force, aging the user.
A caster may become prone to a magical disease/effect, limit to how much one could use/draw on before needing to make checks to resist the disease/effect. Attunement would count towards that limit.
Magic or the potency of magic or the safety of using magic could be tied to specific areas or certain times of the day/year or certain climates.  
Only ritual magic is safe - casting immediate magic results in the possibilty of wild magic.
Magic may alter alignment, erodes virtues or creates additional flaws (temporary or otherwise).
Only patron magic available or reliable.
The language of magic has been lost, burning pages of spellbooks creates limited and/or desired magical effects, but the availability of wizardy material is such that the casting of magic is very precious.

Quote from: Zalman;1144521My own magic system works through the manipulation of daemons trapped in vessels with magical seals. The art of manipulating those daemons is still passed from one wizard to the next, but the means of conjuring those daemons and trapping them in the first place has been lost to time.

I've used something similar:
Magic comes from Demonic Thralls:
Magic comes from the stuff of chaos and a single spell is bound into a demon that has been mastered by the warlock. This mastery is a pure contest of wills between the warlock and the demon. A mastery that is violently resented by the demon and has a very negative consequences when its use is failed and the bound demon breaks free of the warlock's control. The more powerful the spell the more powerful the demon. There is a Contest of Wills to bind a demon for a new spell. If successful the demon is bound and the spell is now available. If not successful then the demon attacks the warlock. Casting a spell is a focus of the warlock's will, with a penalty for number of demons bound. If unsuccessful the demon holding the spell breaks free and attacks the warlock. Each attack forces the warlock to make a Will check. If the check is unsuccessful the lowest level demon still bound is released. This can cascade quickly with the warlock being mobbed by attacking demons.

Little spells and little demons, not so bad. Powerful spells and powerful demons...

Probably the most common background in fantasy RPGs is there used to be a great age of magic, but it's fallen. This has obvious gaming utility, because it provides a justification for all those magic items, allows them to be unreplicable so the PCs are barred from churning them out at will, and also provides a rationale for an ever-escalating set of unknown adversaries, who are relics from a bygone age. This is often accompanied by the idea that magic itself somehow changed, or diminished. The simplest solution is just to cap the power level, like the Forgotten Realms did with the lost 10th level spells, but there are many other options.

One idea I like is that someone is watching. The former age of glory didn't just fade away, it was shattered by an outside force. The watchers may be helpful, trying to bootstrap the current age and raise it again to the heights of power, before the threat that smashed the former world comes back; or they may be malevolent, and a danger to those who seek or acquire power. In either case, they're very powerful, and only pay attention to things that exceed the normal range of power in the world. This could be just tied to level, or something more like a powers check from Ravenloft, where spells or magic of a certain type (extradimensional? wishes?) or above a certain level triggers a roll to see if it attracts their attention.

If the watchers are wicked, they might send random threats or traps; if they're benevolent, they might send omens or challenges. Either way, it's an excuse for random monsters that aren't really random, and spontaneous quests or other artificial dangers that test the party -- the difference between a crucible and a reward, and an attempt on your life and taking their stuff, is mostly tone. More generally, it can explain why things like dungeons and exogenous threats exist in the wider world; dangerous intrusions from beyond can either be designed to cull the hordes of adventurers, or to test their mettle and winnow out the true champions.

The watchers, of course, naturally become part of the endgame; whether they are allies who are helping to prepare you for the end bosses, or the end bosses themselves. Being external to the normal world also allows a phase shift in the campaign, as the PCs leave the mundane world of their origins and either seek the homes of their enemies, or their enemies begin the next stage of an incursion. The most obvious solution is to make the enemies other planar, and to use them as a vehicle to introduce the cosmology. They might be divine, and provide a segue to the upper and lower planes. They might be unnatural, something from realms far beyond the prime. They might elders from an ancient and more primal era, and use the inner planes. They could just be from alternate worlds, or other times. They might be fey from the dawn of the world, the dead bound in books, undead trapped in tombs, natural spirits who are slumbering under the hills, twisted shadows that hide in the dark or mirrors, steampunk empires monitoring worlds, or almost anything you can imagine. They probably control mighty magics, but alternatively could have weird mental powers or technologies.

The psychic connection to the aether that powers all magic was once something only achievable by rigorous mental discipline backed by high intellect, great strength of will, and painstaking ritual technique, meaning that while in theory anyone "could" learn to do magic, in practice it was only the smartest and most strong-willed who could make careers of it. But then some bright spark realized how to create runic patterns, using inlaid silver, that required only a minor level of training and concentration to activate. Suddenly, as long as you had someone with the skill to do the runecrafting (which required much more time but only needed to be done once per artifact), and were willing to settle for a lack of flexibility, anyone could pick up a device and have an effective "spell" in their pocket.

In other words, this is a game setting about the magical equivalent of firearms displacing armoured knights and lifelong-trained longbowmen, and how wizards suddenly have to learn to be not just powerful but imaginative and flexible to add value to their employers.

Quote from: Stephen Tannhauser;1144541The psychic connection to the aether that powers all magic was once something only achievable by rigorous mental discipline backed by high intellect, great strength of will, and painstaking ritual technique, meaning that while in theory anyone "could" learn to do magic, in practice it was only the smartest and most strong-willed who could make careers of it. But then some bright spark realized how to create runic patterns, using inlaid silver, that required only a minor level of training and concentration to activate. Suddenly, as long as you had someone with the skill to do the runecrafting (which required much more time but only needed to be done once per artifact), and were willing to settle for a lack of flexibility, anyone could pick up a device and have an effective "spell" in their pocket.

In other words, this is a game setting about the magical equivalent of firearms displacing armoured knights and lifelong-trained longbowmen, and how wizards suddenly have to learn to be not just powerful but imaginative and flexible to add value to their employers.

Eh, just use gunpowder and price "artisanally cast fireballs" out of the market.

Quote from: RandyB;1144544Eh, just use gunpowder and price "artisanally cast fireballs" out of the market.

True, but gunpowder doesn't work when wet: a weather or water mage can render your bombards and fusiliers useless. Or a fire mage can spark off your powder stores at a distance.

Quote from: Stephen Tannhauser;1144566True, but gunpowder doesn't work when wet: a weather or water mage can render your bombards and fusiliers useless. Or a fire mage can spark off your powder stores at a distance.

Can they? We know how gunpowder works, because we have extensive experience in the real world. Yet magic, particularly the magic of high fantasy, can do nearly anything. But in an RPG, magic can't be a simple plot device, instead it needs precisely defined and consistent limits. And once that's established, your water mage's range might to too limited to be effective on the battlefield, a weather mage might be defeated by a few tarps, and a fire mage might only be able to manipulate existing fires instead of creating new ones. So you really can't talk about specific countermeasures, until you define the limits of magic.

And if magic is reasonably well defined, and one option isn't completely superior to the other so there's that give take, it's likely that the option that allows mass production and no natural talent or extensive training to use (gunpowder, presumably) will become far more common, with the artisan option (likely magic) relegated to more specialized uses.

Quote from: Pat;1144586And if magic is reasonably well defined, and one option isn't completely superior to the other so there's that give take, it's likely that the option that allows mass production and no natural talent or extensive training to use ... will become far more common, with the artisan option ... relegated to more specialized uses.

Well, yes. But since the thread is about changes in magic I think it's reasonable to exclude purely non-magical technology from the discussion, at least for the moment.

That said, you're also right to point out that mass production and reductions in required training create objective advantages for any technology -- and in the vast majority of RPGs magic is effectively a technology, in that it is (for its users at least) a reliable way to accomplish predictable effects. So any RPG setting where magic loses some of the advantages it's historically had as a player option is, in practice, going to fight an uphill battle, because the novelty of the difference tends to wear off pretty quick.

Quote from: Zalman;1144521My own magic system works through the manipulation of daemons trapped in vessels with magical seals. The art of manipulating those daemons is still passed from one wizard to the next, but the means of conjuring those daemons and trapping them in the first place has been lost to time.

I like that idea, seems like it would lead to an economy of magic that would promote ruthless competition. I'm also always in favor of things that limit the commonality of magic in a setting. Magic that's too prevalent would have such large scale societal impact that it sort of bugs me not to attempt to flesh it out, and that's a headache.

I like the idea of magic as a corrupting influence and having penalties for extended use against ability scores and/or skill checks.

Quote from: Stephen Tannhauser;1144596That said, you're also right to point out that mass production and reductions in required training create objective advantages for any technology -- and in the vast majority of RPGs magic is effectively a technology, in that it is (for its users at least) a reliable way to accomplish predictable effects. So any RPG setting where magic loses some of the advantages it's historically had as a player option is, in practice, going to fight an uphill battle, because the novelty of the difference tends to wear off pretty quick.

They go back and forth on that. In Ars Magica or GURPS, making magic items is very much a craft that can be practiced on a large scale. But in AD&D1e it was largely the DM's discretion, in 2e they threw in some fairy tale logic, then in 3e it became industrialized. But you're right, minus item creation, the practice of magic is almost always mechanized. But it's worth noting that it's usually only clearly defined in terms of game mechanics, not in terms of the world. We know a lot about how gunpowder works, but a fireball might just be this thing that does 10d6 damage in a specific area. That leaves a lot of room for interpretation, which is why precedent and table standards matter in RPGs.