OSR: Wards and Counterspells

Over on discord, evilscientist42 asked if there were any good counterspell rules. They published their own before I had a chance to finish this post.

True counterspells are dedicated spell-eating spells. A shark, to pierce and burst incoming magic. Variants include stifle, deflect spell, and Horsbraile's Needle of Thaum. A dedicated counterspell gives you more power for your charge, but requires a spell slot.

Some wizards see them as cowardly. It wastes an entire spell slot on the possibility someone will cast a spell on you and you'll have time to react and you have sufficient charge to do something about it. Wizards tend to think in terms of "doing unto others."

Traditionalists and novelists love thematic negations. Ice ray vs. firebolt. Reality rarely obliges.

Biffno

Charge

The Magical Industrial Revolution has significantly altered the availability of raw magic. The largest magic battery in the current Ioderth range, the "Gargantua-II", can store more thaumic charge than the legendary Flying City of Augh [1] used in its entire operational lifespan.[2] 

This is because a magic battery has only one job: storing magic. It doesn't need to do taxes, navigate traffic, or dream of a better and more remunerative future.

Strictly speaking, the human brain doesn't need to do any of these things either, but it tends to be used for more than just storing raw magic. Learning to carry a charge without detonating is part of wizarding training. Learning how to release that charge into a spell without accidentally fulcruming your brain through your ears or blowing off the ends of your fingers is an equally important part.

An untrained human being can store just enough magic to find their keys in the dark, create true love from reasonably priced ingredients, or run into a burning building to save a child. With time and effort, a human can store significantly more thaumic charge without exploding. The first humans who figured this out became wizards, or druids, or seers, or merely very good at hunting mammoths. Magic has come a long way since then.

[1]. Full name: "Augh What Is That"
[2]. Approximately eleven minutes.

João Bragato

Improvised Counterspells

Instead of relying on a dedicated spell-killing-spell, some wizards simply dump raw magic into the atmosphere. Weak spells overload and fall apart as the thaumic gradient switches direction. It's seen as a sign of fear and lack of control, but history is written by survivors. Survivors who might be missing the tips of their fingers, but survival is survival.

Improvised Counterspell

For GLOG wizards. Acquired at Wizard Template C.

As a reaction to a spell that targets you or passes near you, after your opponent rolls their MD, spend any number of MD. 

• If your [sum] beats their [sum], the spell is cancelled. 
• If your [sum] equals their [sum], the spell detonates. Default is half the distance between you and your opponent, radius [dice]x10', [their sum]+[your sum] damage, Save for half. 
• If your [sum] is less than their [sum], the spell is cast normally.

MD invested in a counterspell do not return on a 1-3. Do not generate Mishaps or Dooms.

Mechanical Notes

This gives wizards yet another use for MD. Knowing your opponent's [sum] before deciding whether or not to counter makes it less of a gamble and more of a calculation. If their [sum] is 5, do you risk 1 MD or use 2? If their [sum] is 16, even 3 MD probably won't help. 

I feel like having returning MD would tempt players to use the ability too often. It also makes thematic sense; you're not metering out your magic, you're dumping it blindly.

Pavel Kolomeyets

Wards

A spellbook page traps a spell without being, itself, a spell or bound enchantment. Similarly, a ward alters or deflects magic by its substance and structure. As a spellbook page resembles, thaumaturgically, a cozy human brain, a ward can resemble a wall, a mirror, a spiral, or a key. It's all about shaping the flow of ethereal forces. A circle is the most basic thaumic shape. 

Wards are a trade between cost (low), time (high), expertise (fiddly), and effectiveness (never as much as you'd like). There's a saying: "a well-made ward gives you time to worry." 

Many a fine wizard has spent years engraving their workshop with wards, only to slip on a dribbly candle and knock their head against decorative pewter candlestick.

Salt
Cheap, simple, and never as effective as you want it to be. Your average poltergeist will be stopped, but any ghost serious enough to worry a wizard will simply melt its way through, in time. The last thing many exorcists see is a pleasant orange glow.

Bone
A bit gauche these days, but bones earth all sorts of magic. They're at least six times better than lead, and you can mine them in any major city. Chalk is just another kind of bone, so whenever you see a wizard marking symbols in chalk, know that their forebearers would  have marked them with burnt femur.

Blood
Extremely gauche and very unreliable. Still, prudent wizards keep a cage of mice handy. Blood wards lose effectiveness as they dry, but fresh blood has unmatched potency.

Copper
Conducts stray charge away instead of absorbing it, which is good if you like your wards to be reusable. Wizards traditionally connect copper earthing strips to a dried crocodile.

Rules for Wards

A well-made ward (at minimum, 3 hours for a 5' circle) gives you (inclusively):

• Knowledge. You know if a designated creature type or spell crosses your ward. 
• Obscurity. Precisely targeted spells (scrying, teleportation) are distorted by wards.
  
• 1 round of extra time. A fireball sizzles in midair. Lighting burns but does not strike.
• 1 point of damage reduction. 

You can layer wards, and the results stack, but each layer doubles the time required.

Any solid object can be warded, but the math for warding a coat with silver embroidery thread is much trickier than a nice chalk circle on stone.

Wards have a 50% chance to fail after use.

Wards work both ways. If you ward against scrying, you cannot scry out. If you ward against skeletons, do not move quickly across the barrier.