Zero Sum Game (A Magic System)

This is a detailed alternative magic system focused on making magic far more impactful and visceral, along with a few pieces of supplemental material related to the system. Feel free to do with these ideas as you will. 

HOW MAGIC WORKS
(Art by Sergio Toppi)

In The Age Of Timeless Wisdom, magic was taught in schools and cultivated through countless decades of training and study. You do not belong here - you were born red-faced and flailing in a crater that used to be a palace. The Age Of Everflowing Blood welcomes you with open arms and gnashing teeth.

This new, violent age was spurred into existence by a senior thesis which proved the following:

1. Spells are stored in the cranium.
   
   
2. Magic can be harnessed by anybody - contrary to popular belief at the time.
   
   
3. ALL of a wizard's spells can be learned by killing them and consuming their skull. This takes about one night of very careful meal prep.
   

Since this discovery, the socratic methods have been lost in a cannibalistic fervor. Those who had the patience to educate have been eaten by the impatient. The hopes of learning magic in any other way have been dashed against stones of ivory. 

Countless spells have been lost to The Age Of Everflowing Blood. There only exists a single copy of every spell. There is only one Fireball left in existence, one Charm Person, one Healing Word, etc. To know a spell is to have stolen it. To call oneself a wizard is to call oneself a murderer.

 

NOTES ON WIZARDS AND OTHER CULTURES
(Art by Sergio Toppi)

  

Across every horizon it's a dog-eat-dog world. But wolves still travel in packs, and wizards still find power in company. One would assume that a group of wizards would quickly murder one another for a glimpse of power, and they would only be partially right. All wizards have a biological life insurance - once a wizard dies, ALL of the spells stored in their head are cast one last time in random directions and at random targets within sight. This is called a deathrattle. Thus, wizard-murder must be carefully premeditated. You know the old phrase, "if you can't beat them, join them". Wizards form dysfunctional families bound by envy and mutual destruction until one feels superior to the others.

If you look to the safe, shadowy spots of the world, you may see figures huddled against the ashen wind. Hushed tones indistinguishable from the campfire's hiss. They speak of the dragon atop the hill. They speak of a wizard. If you are revealed as a wizard to commonfolk (whether willingly or not), reroll your Reaction Roll - positive results leave them terrified instead of friendly. It is near impossible for magical folk to find true kinship with mortal folk.

Then there are those mortal warriors brave enough to face wizards head-on. Those that believe a good butcher is a careful one, a good wizard is a dead one, and a just man is a poor butcher. When you crush a wizard's skull in haste it will once again perform its deathrattle. After this is done, the skull cannot be crushed or consumed. These acts are reviled by all wizards. They think it no different than bookburning. Plenty of hearts driven by vengeance still stake it all to see sparks fly out of those accursed sockets that have hurt the world so.

Similar to a murder of crows, a group of wizards is called a School. Gluttony is their teacher. Their lessons are cruelty.

FIVE SAMPLE SPELLS
(Art by Sergio Toppi)

 

FIREBALL - R: 120’
Launch a ball of fire that explodes in a 30’ diameter sphere, dealing [SUM] fire damage to everything within. Optionally, choose an extra effect below per MD invested past 1:

1. The affected area is filled with a cloud of opaque, choking smoke that lingers for [SUM] rounds. Breathing beings take [DICE] damage per round spent in the smoke.
2. Double the diameter of the explosion – triple if you take a round to monologue beforehand.
3. Double the amount of MD you’re rolling - triple if you take a round to monologue beforehand. On triples, catastrophic miscast. An effective last resort.

Drago The Cannibal King used his great Fireball to destroy the great libraries of the old mages, ensuring nobody could learn magic through the old methods and securing his place as the dread Cannibal King. His territory is a large crater host to an invisible tower - the air still smolders with burnt paper.

HEAVEN’S MANDATE - R: All Targets In Earshot, D: [DICE] Rounds
Speak a command of [DICE] or less words. Choose one of: Light / Gold / The Pious / Canines to obey your command. If applicable, sentient beings will not obey commands obviously harmful to themselves. Optionally, choose an extra effect below per MD invested past 1:

1. Choose [DICE] extra options to obey your command.
2. The command may be [SUM] or less words.
3. The spell lasts [SUM] minutes.

Neri The Beloved used her Heaven's Mandate to create The Grand Procession, trapped in an endless task of building statues in her image. Her territory is a long trail of tarnished golden statues that are rumored to come to life at night.

DRUID FOG - R: All Targets In Earshot, D: [DICE] Rounds
Conjure a cloud of fog in a 30’ diameter sphere. The cloud is opaque and supernaturally confusing - creatures entering the cloud will exit they way they came in [DICE] rounds. Optionally, choose an extra effect below per MD invested past 1:

1.  Imbue the fog with a drug on your person. Creatures inside must save or be affected by the drug. This save is made with a [DICE] penalty.
2. You can see perfectly through the fog. Those with your permission may pass through the fog unhindered.
3. Ignite the fog with a snap of your fingers, dealing [SUM] damage to all inside and knocking them prone. 

Baldovi The Hermit used his Druid Fog to shroud an entire city he despised in fog, driving all the souls within mad. His territory is this city, his subjects are driven to his bidding by hallucinations within.

CONJURE ARMS - R: Self, D: [DICE] * 10 Minutes
Grow [DICE] extra arms anywhere on your body, under your control. Optionally, choose an extra effect below per MD invested past 1:

1. The arms you conjure are [DICE] * 5' long. You have perfect control of them. They have an unnatural amount of joints. 
2. You may cast this on an object you can touch. The arms are under your control.
3. Conjure double the amount of arms - triple if you give the arms their own control. 

Livio The Monster used his Conjure Arms to abandon his humanity for more arms and more power. His territory is a great castle in the sky that is held up by thousands of long spindly arms that snatch stone from the land below.

BECOME LOCUSTS - R: Self, D: [SUM] Minutes
You and your equipment transform into a swarm of locusts. You take 1 damage from anything that does not affect an area for the duration, and you may fit through anything a locust may fit through. There are enough locusts in the swarm to lift a toddler. Optionally, choose an extra effect below per MD invested past 1:

1. Instead of transforming into locusts yourself, summon a swarm that you have complete control over. The spell lasts [DICE] hours.
2. There are enough locusts in the swarm to lift [DICE - 1] adults.
3. Instead of becoming a swarm, become one massive locust the size of a cabin.

Black Mele used his Become Locusts to create an army of monstrous insects under his command. His territory is a great fortress made of chitin, surrounded by toiling uplifted insects.

Should you do something (in)famous with a spell you use, you may add an extra custom-made option to the list of extra effects. Negotiate with the GM on this effect. Legendary wizards have many different ways to cast and amplify one spell to dangerous effect.

SYSTEM-AGNOSTIC CONSIDERATIONS AND DESIGN NOTES
(Art by Sergio Toppi)

Talking more casually, I know that's a lot and you may have the question after reading this "okay, how can I use any of this". I bolded the important stuff that makes up this magic system (I like to call it Zero Sum Magic), which you may steal piecemeal or wholesale for your games. In summary, from most critical rule (in my opinion) to the least:

1. There is only ONE of each spell in existence. One Fireball, one Charm Person, one Healing Word, etc. To own a spell is to have stolen it from someone else - nobody is born with magic.
   
   
2. You can learn ALL of a wizard's spells by consuming their skull. Anyone can do this.
   
   
3. The first time you consume a wizard's skull, you gain the ability to cast magic. If you're using GLOG, this means you gain 1 MD. If you're using some other system, this means that any class requirements that may have prevented you from using magic are removed.
   
   
4. On death, a wizard's skull casts ALL of spells stored inside it in random directions, at random targets, all within line of sight of the skull. When a wizard's skull is crushed in haste, it does the same, but it can no longer be consumed. This makes it a risky proposition to kill a wizard, the crime must be done with care.
   
   
5. Wizards can reroll reaction rolls toward commonfolk by revealing they are a wizard - positive results leave them terrified instead of friendly. (Thank you Archon for this idea)
   

Mechanically, levelless spells work best here (like ones present in Marvels & Malisons, etc), as it's disappointing to strategically kill and consume a wizard only to learn that all the spells they own you cannot cast yet because you're underlevelled. GMs, be unafraid to let your PCs play with fire!

In playtesting I've found that you should really make spells more powerful than you'd instinctively make them typically if you're an OSR GM. Think of them almost as superpowers. The example spells I list are made more powerful by adding more benefits if you gamble with more dice. Speaking of which, I highly recommend using a spell system where spells can fail somehow - it adds to the drama. Try not to make the failure "the spell fizzles", make it bombastic, make it complicate the situation - sometimes even make the mishap possibly work in their favor.

All the extra options beneath the example spells serve to broaden their use cases - as useful a spell something such as Knock is, it feels bad to be sold on the fantasy of being a powerful wizard with truly unique spells and having a spell that has very limited usage. I generally try to make most spells have some offensive use-case despite the general OSR tendencies to lean away from that. Typically the list of extra effects can be a great place to shovel in extra use-cases to really round out a spell. I recommend you model your own spells in a wizard-focused game like this after the example spells.

 I find an easy way to come up with a spell is to work backwards and come up with the wizard first, since here magic is connected to someone's being instead of a book. Additionally, if there's some sinister or strange phenomenon happening in your world, make a wizard responsible for it! It immediately gets the players imagining what they could do if they had that kind of world-altering power. A good player is a greedy player, so keep them hunting.

I can't stress enough how much you should be unafraid to let PCs play with fire. Watching them get burned makes for memorable play.