How do you all treat magic in RPs, if existent? Do you apply a set of natural rules that dictate magic, as physics does the physical world? Or is it anywhere you damn well please? I wonder this because a RP server for Minecraft I use to kill time features magic, generally as a way to explain why the admin likes to have bullshit plugins (I feel). Lore-wise it seems Magic has no real rule or grounding set of natural laws. It's diffuse and all over, and it's evident in its Wikipedia. There's maybe something like five totally different schools doing various things and not once has anyone asked, "So what says this works?" The closest to a rule this thing has is that most often magics involved other worlds. But still, no one has explored anything beyond that. They're too busy using world-ending demon summons that are accidents as plot devices and I'm about ready to call the execution of all mages, spellcasters, and shit. So gentlemen, where and when it's applicable how do you use or regulate Magic? Outside of DnD stats. how is it regulated as a natural thing with understood or with rules that can be explored, with natural effects both good or bad in your world? I'm personally a fan of the effect of the spell being directly proportionate to the cost to utilize it, with other "modifiers" attached. To kill a target, you must first sacrifice someone else. But this may then take time, since in this it presumes the spellcaster is using spirits or ghosts to do his bidding and he knows how to use them. However they do demand a equal or greater price. As a NRP'er primarily I think this works well into the hands of balancing across the board since it gets people to think about what they're doing. This also comes with the possibility of there being lore implications like the study of how to use spirits as conduits of magic comes with a great deal of study. Study that may be so intense you become a hermit or socially isolated as you read and practice. And the equal cost to effect of certain spells would make someone either dangerous, or incredibly eccentric and not well seen in the public eye. It's the sort of thing that I discovered comes up in The Witcher when I actually got into the series later. Mages and other magic types are rare and their studies are rigorous. And due to their overall rarity and eventual isolation from the world a matured and practiced mage may be treated with a lot of contempt and scorn. Even if they manage to become powerful in royal courts - where they ultimately end up - they still get the treatment. And throughout the history of The Witcher wizards have been executed and hunted for their abilities. So needless to say, I'm not one for uncontrolled "everyone can do it" magic. Or if it's presented as easy to get into while someone weakly says it's not.

I like to apply loose physics to magic. In my current game, I'm using a pattern-based magic system: certain materials under certain conditions will create a specific result. Like in the way that a harmony of heat, fuel, and oxygen can create fire. Certain natural patterns are capable of creating energetic reactions. Certain rudimentary totems (what I call them) are two-dimensional patterns that can be created with simple lines in dirt or paint on a wall. Other totems are three-dimensional shapes, like knots of copper wire in intricate weaves, or a complex spiral of blown glass to a precise volume. Generally, the more complex the pattern and rarer the material, the more powerful the effect, though this is not always true. In this way, a character must have the right materials and the right items to create the right sort of magic. And I like the magic systems that adheres to "...equal and opposite reaction," so your example of directly proportional spells are up my alley.

The Darksun setting from D&D had magic be powered by life. Powerful spells could turn nearby plant life to ash, and large scale mage wars are how Athas became basically a desert planet. The few who still use magic are either Preservers or Defilers, Preservers are very careful to not take too much power and make sure they don't kill things by taking too much, while Defilers don't care and are happy to ruin land to fuel their magic.

In my Allaria RP, all magic was based on the soul. The more you used the more of your soul, which would regen, was burned up. With a soul nearly gone, you couldn't summon your spirit animal, use magic, or communicate with Gods. As far as types, it was mainly do as you will but time and space any excessive teleporting was out. I am a fan of Erikson's magic in Malazan Book of the Fallen, where it wasn't particularly outlandish and not everyone could do the same thing. It was based on Warrens, or other realms, and very few could access more than one - and almost no one changed Warrens(only memorable mention was Deadsmell going from Necromancer magic to Omtose Phelleck, or rather Ice Magic, when Hood, The God of Death, was killed and sent inside a sword, instead to the Underworld. When he was released from the sword, he returned to his original state, a Jaghut meaning he went back to Ice Magic - ergo so did Deadsmell and presumably many other folks whose magic was based off Hood. none were mentioned, however)