Magic obliterates its user upon critical failure

Not at all. You can't crit-fail skill check.

Create a magic item that's incredibly unstable and can be "cast" by anyone within a large radius of it once activated.

You just pull the pin or whatever and lob it at your enemies, they involuntarily activate it, the magic fucks itself up and poofs your enemy.

There's probably a better way to weaponize this, but this is the best I could come up with off the top of my head.

>This spell uses very slightly different wording guys!

No, no. No, you're still dead, but now your friends have an inert likeness of you.

have you heard of the world of Warhammer 40 000?

This.
It is literally one of the things that can happen to a psyker.
You are fucking dead, and NOTHING can prevent it, outside of the handful of ways you can negate a peril result.
But once you roll the dice, you are done.

Humans are gone.
The VRS consumed every other race and what was left of the humans.
Junkers never came to be, neither did Poppets.
On the plus side, Ground Nil never happened, and there's a lovely oasis there now that the VRS built a city on.

Oh, and the Star Elves settle on a floating island instead of a coastal mainland region and make VRS-surfing a national sport.

Why would you try to screw over spellcasters and discourage people from playing them when you could instead just make a setting without spells and magic to begin with?

>A moreinteresting system might be going back to classical and mythological depictions of spellcaster is where they have to summon spirits and make bargains to get anything done
This makes me think it would be interesting to have a campaign where "Greater Elementals" and forging pacts with them is a major plot point.

If you want to offer a balance for spellcasters to not be broken, a better method would be simply to have Natural 1s invoke a 1d10000 Wild Magic table.

>implying that would prevent murderhobos from using magic
arrogance and confidence exist user, also desperation, and of course
>what are drugs
magic can be highly addictive

So lifting the mechanism for making pacts with demons from Chaosium's Stormbringer?

I was thinking more along the lines of The Tales Series.

It doesn’t, because my core setting’s magic works fundamentally differently than that, as it is an exertion of personality against personality.

However, if magic is actively punishing I prefer to just have proportional backblast.

I have this for divine magic in my setting. Divine magic is the most powerful, as it uses the force of the creators power to warp reality directly, but prior to the events of the story, the priestly order fell from grace. Now the magic still works, but users run the risk of the creator noticing them, in which case under the gaze of the divine the caster and everyone in a 10+ metre radius is burned from existence, no afterlife, no remnants, nothing.

The remains of the priesthood that haven't renounced faith either studiously research how they might have lost favour, or learn other schools of magic. A few near madmen sell their still unstoppable abilities to the reckless men in power who can afford the risk of hiring a bomb that could blow up in their face at any time. They're not used as a player class, used more for plot device/spec into if my players really want.

If magic is performed as a group, do they all die, or does the leader die, or does a randomly selected sorcerer die? This probably matters.

Anyone who plays with my setting homebrews that rule out, because it's fucking retarded. That's how it affects my setting.

>Time magic doesn't work
So, what, if I go back in time to stop them from casting the spell they're already dead? If so,t hen the whole world is constantly changing as people fuck up a spell to the point of getting erased from all of time forever until we get to a point where nobody is casting magic, magic doesn't exist, or nobody knows magic exists. If it's the last one, it keeps repeating ad infinitum

>90% of 'magic schools' are really just scams to get a fall guy for whatever spell they cast
>Instead of death row or the noose, people are sent to the wizard colleges
>Raiding parties and slavers are always on the lookout for magical gifted children, which fetch the highest price

why? Are you saying you will only play a game if you can play a spellcaster?

Does the percentage chance of critical failure increase proportionally with regards to the power level of the spell? Because if not, everyone dies as an apprentice.

Obviously players would only ever do it when theyre going to die otherwise

>How does this affect your setting?

I already have something like this if anybody happens to give a shit.

When you use magic you're using your soul to directly interact and change the 'soul' of other things in the world, but if you do it wrong it can have the opposite effect.
People are naturally shaped by the magic they use, whether it be: arcane, divine, demonic, or naturally occurring, but more to the point.

If you do arcane magic too hard (I.E: classical wizardry, alchemy, light and noise, books n' magic missiles) your soul can actually forget what you look like and end up having your body contort, melt, and mutate into a picasso painting. If you're lucky you die, but some people survive this process and have to live on as post-modern art... The silver lining, though, is you become TERRIBLY good at arcane magic from that point onward.
Divine and Demonic have this problem in small, thematic, packages as you'll take the genre-savy flavor of whatever patron you've been leasing magic from, but Nature magic technically 'doesn't' in the sense that you're not actually changing, but becoming a more 'purer', 'truer', form of yourself- you're being polished into your primeval self.

everyone just takes 10 on spellcasting

What if you make a clone of someone, and have it clone itself, and so on until eventually one of the clones has a crit fail. Does that kill the someone you cloned?

No, but it's more fun if I am

>Cannot reroll or luck it
>luck altering mages rule the world
How do you figure that would work, champ?

Dark Heresy did this. They realized that over the course of a campaign even at 1% chance or less, the horrible thing will always happen and people won't do the thing that risks it.

So they got rid of that immediately.

THE SEEA KIING
HAS COME TO HIM

>magic is dangerous and really costly!
How are you not fucking bored to tears of this by now? Honestly, did the "you all play as level 1 commoners because playing the inept is totally an interesting subversion guys" get a new meme to push? 40k rpg is the only execution of this that really added to the game and didn't feel like a lazy way of balancing things.

I prefer the old Paladin rules, altered to fit wizards and mages of intellect.

>A mage is a highly intelligent motherfucker.
>If he performs an act of stupidity, he risks falling and being unable to use any of his wizard spells or abilities until he atones for his idiot-ass actions.
>Atonement is usually done by confessing to a wizard of your particular focus, e.g. an abjurer or a conjurer, getting laughed at for being so goddamned dumb, and then getting sent on a quest to fetch a pail of water with your incredibly feeble mortal muscles or something equally humiliating.

Turnabout is fair play.

So basically it's WHFRP except you can't use fate points anymore.

Well, spells have no chance of failing in my setting, so nothing changes.

a 1 on a d20 is critical failure?
wouldn't take long for the magic user to die I guess

A lot of people might also try magic as a last resort.

Magic becomes the field of casting "Summon fey-book" which permanently summons a sprite that is bound to you in spirit and mind, and will birth up to 15 wish-children a day who each can cast any magic their mother knows, but die after one day anyway and are also bound to you.

Magicians can study for years to make sure they can cast the spell, and after that, all of their magecraft is teaching their fey-book more magic which casts it through their wish-children.

You should never balance a mechanic around it being unfun/unreliable to use.