Spellbuilding Part 1 – Simple Conversion

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The first part of the spell building system covers situations like finding a really cool spell that seems difficult to quantify or that you do not want to breakdown and rebuild. It is a fairly simple system to use spells from any OSR system, or retroclone OGL content. Before starting on that, here are the basic mechanics of the spell building system.

The system adds point values based on effect, range, duration, and any possible areas affected by the spell. The total is the spell’s difficulty rating. Success in casting a spell is determined by rolling 1d20 + Intelligence score + Magic-Users’s level to equal or exceed the magic-user’s Saving Throw + difficulty rating. At the referee’s discretion, a difficulty rating can be converted to a spell level for use in Vancian spellcasting. Like Cleric spells, converting a difficulty rating to a spell level is reversible.

This may seem like a mouthful, but to help with ease of calculation, I put Intelligence score + Caster Level on the character sheet. You’d think this wouldn’t be a big deal, but it seems to make calculation easier. Since the Saving Throw already appears, it is just a matter of looking up the difficulty rating in the spell book.

In this post, I’ll be taking OGL spells from various places and converting them to a difficulty rating.

Simple Conversion to a Difficulty Rating

Use the table below to convert spells to a difficulty rating:

S&W Spell Level Rating
Cantrips† 7
1 11
2 15
3 19
4 23
5 27
6 31
7 34
8 37
9 40

†Cantrips cannot do any damage. Using cantrips assumes the use of Tim Brannan’s Cantrips for Basic Level Games system.

The difficulty rating in the table above is the midpoint for a spell level. Feel free to adjust the difficulty rating up or down by up to 2 points. In other words, a second level spell can have a difficulty rating from 13 to 17.

In looking for spells to serve as good examples, I looked for OGL spells from the LInks to Wisdom section on spells.

First, let’s take a look at the Dreadcube (click the link for a full description). It is listed as a 7th level spell, so the new difficulty rating for this spell would be 34. It has multiple effects, so normally, I’d adjust the rating up, however, these effects can also potentially harm the caster, so I’ll leave it where it is. OGL Link for Dreadcube

For those that wonder about the odds, let’s take a magic-user with an INT 13 (the minimum score required to cast a 7th level spell). We’ll say that the magic-user is at 14th level. The M-U will roll 1d20 + 13 (Intellegence score) + 14 (Caster Level) to be greater than or equal to 5 (Saving Throw at 14th level) + 34 for a total of 39. The magic-user will have a 45% chance of successfully casting the Dreadcube.

That seems a bit low, but 13 is the minimum Intelligence to cast a 7th level spell. Most Magic-Users for my players have an INT of 15 or 16 at least. Just for the sake of comparison, a 14th level Magic-User with an Intelligence of 15 attempting to cast this spell has a 55% chance of success.

Here’s another favorite of mine from the Space Age Sorcery pdf, Pretervolve. (click on the link to download the free version). It is listed as Level 5, so the difficulty rating is 27. Seeing as there is a permanent effect after the spell wears off, I’d add a point to make the final difficulty rating a 28.

Again for the odds, we’ll say that a 9th level Magic-User with an INT of 13 will cast Pretervolve. The M-U will roll 1d20 + 13 (Intellegence score) + 9 (Caster Level) to be greater than or equal to 7 (Saving Throw at 9th level) + 28 for a total of 35. The magic-user will have a 40% chance of successfully casting the spell.

Again, many characters will have a higher INT score. A 9th level Magic-User with a 15 Intelligence score has a 50% chance of success.

Section 15 of the OGL for the Pretervolve spell is:
Space-Age Sorcery, Copyright 2013, Hereticwerks; Authors James Garrison, Eric Fabiaschi, Porky

Here’s another favorite, the Auric Devourer (read the post for the full description). It is listed as 1st level, so I convert the difficulty to 11. Since the description states that it is easy to cast, I’ll bump it down to 10.

I’ll come back to this spell another time when going through the building system itself, because it mentions other factors that will be covered later. It has a listed casting time and an area of effect.

Really quickly, a 1st level Magic-User with a 13 Intelligence will have a 50% chance of success to cast this spell.

Lastly, let’s mention the Cantrips. They are not necessary at all, but I mention them here because they add something fun. Using the table, Blackflame starts at a difficulty rating of 7, and I’d leave it at that. Looking at other cantrips in the list, I would probably make Flavor a rating of 5. The key to using cantrips is that they cannot do any damage. Regardless of difficulty rating, any spell that does damage must be at least a 1st level spell.

A 1st level Magic-User with a 15 Intelligence (to represent most player characters), will have an 85% chance to cast Flavor and a 75% chance to cast Blackflame.

Using Difficulty Ratings with Class

Okay, I can turn a spell level into a difficulty rating. Now what? How does this work?

At this point, you could use the Spell Point system I mentioned to track the ability to cast spells. The cost of casting the spell is the spell level. Casting a spell deducts from a character’s Mana and when Mana is zero, no more spell for you.

For your conveience, here is the table for Mana per level.

Level Mana
1 1
2 2
3 4
4 7
5 11
6 16
7 21
8 27
9 35
10 44
11 54
12 65
13 77
14 90
15 104
16 129
17 145
18 162
19 180
20 200
21 222

If the referee prefers, the traditional spell slot system can also be used.

Another alternative is to say that a Magic-User can attempt to cast a spell in his spellbook until it fails. If the Magic-User has Sleep in the spellbook, he can cast it until the dice betray him. For low level magic-users, this means that they can likely cast more spells per day, but it removes the need for bookkeeping.

Next time, we’ll look at building spells based on effect, range, duration, and other factors.

Sachima – A New Race

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Sachima describe their existence with a story. It begins with Amnaté, a very old and powerful dragon. Although wingless, he soared over his vast holdings of land navigating the space between earth’s magnetic field and the ever-present winds. He was proud of his great wealth and fair dealings with mankind. He could have destroyed them all, but instead chose to spare them.

Amnaté was lonely. He would go to their cities in human form and revel in what seemed to be their endless celebrations. Yet after the festivals ended, he returned home more sad than before. He struggled to understand what motivated mankind to have these festivals.

Satva enoyed roaming the countryside and running free. She had no mate and had no need of one. Were it not for the endless celebrations of mankind, she would have remained solitary to her last day. Despite their mystery, she found mankind to be quite amusing.

Like all cats great and small, she would curiously enter towns and villages to see what would happen next. Sometimes she went as a small cat, other times as a human. Mankind feared tigers and she would never presume to interrupt their parties with her true form.

At one Festival of Spring, Satva found someone that appeared to be sad despite the revelry that surrounded him. She went to him as a small cat and offered purrs to comfort the man. They appeared to have no effect. He mindlessly stroked her fur and sighed. For his indifference, she hissed and scratched his leg.

Amnaté was startled by the attack. He understood sadness and the pointlessness of the festival, but he was intrigued that any creature that could be so angry at a party. He went to find the cat, but it was gone. Feeling sad once more, he went to return to his seat, but decided to find the cat instead. He searched the city with no success. Many shurgged when asked if they had seen the cat, but a kindly older woman offered to help him.

“Cats are fickle,” she said, “it wouldn’t have scratched you if it didn’t have some interest in you. I bet if you go home, it will follow you. I will come along to help. Don’t turn around to see the cat. If you seem interested, it may decide to stop following you. I’ve known many cats in my day, it will not concern itself with me.”

Amnaté agreed and the two began traveling to his home. As they talked, he felt the pleasure of excellent company and the sharp pain of knowing his companion would be gone when he arrived home. Instead of taking a direct path, he took meadering trails and overgrown paths until they reached thick, dark forest.

A demon appeared saying that he would enjoy eating this foolish couple that dared wander into the dense forest alone. Amnaté swore to the woman that he would protect her, but that she had to run a short distance away without looking back. When it appeared she had gone far enough way, Amnaté changed into his true form.

The demon plead for his life, running away when he saw the great dragon build the fire in his nostrils. No sooner than he had gotten away from the dragon, a great tiger leaped upon him tearing at his demonic flesh. In fighting off the tiger’s claws and teeth, the dragon caught up to the hapless demon.

“This demon attacked my companion!” Amnaté roared, “Let me relieve my wrath upon this fiend!”

“Why are you interrupting my play?” the tiger growled back, “This thing is no threat to you or to me.”

Biting the demon on its shoulder, the tiger hurled the demon deeper into the wood. Licking the blood from its teeth, it lay down to groom.

“How dare you!” The dragon roared.

“Oh be still, Amnaté,” the tiger purred, “didn’t I tell you that the cat would follow you home?” At that, she transformed into a young woman and walked closer to the dragon.

“What sorcery is this?” Amnaté stammered, “Are you the woman that traveled with me?”

“I was interested.” Savte replied, “And you were feeling so alone.”

Amnaté changed into his human form. After some time, the two traveled to his home. Not long after they were married. Relatives of Amnaté and Savte soon moved into the kingdom and the land flourished.

The Sachima claim Amnaté and Satva as their ancestors. To be Sachima is to explore their draconic and tigrine heritage. Like dragons, they are proud and powerful. They are intimately familiar with ancient forms of magic, but judicious in its usage. They are innately curious, eager to learn new things. They also have a profound sense of play. Although generally amicable, Sachima are methodical, ruthless, and efficient killers when attacked.

Sachima can see in the dark up to 60 feet. They receive a +4 bonus against breath weapons and have a 2 in 6 chance of being able to communicate with any type of cat.

Sachima can advance to 10th level Magic-Users, but have no level limit as Theives. Sachima also have their own peculiar type of unarmed fighter that employs a handful of spells delivered as a breath weapon. There are no Sachima clerics.

If the Emphases system is used, Sachima magic-users automatically have dragon and big cat emphases.

The Abandoned Study of Zhanguo Jee

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I mentioned in a previous post about creating spells with a mechanical element (number crunching) and a narrative element. It occured to me at some point tonight that a narrative tag, which I call an emphasis, does not have to be a part of a spell, but can function as a material component or a spell focus.

Let’s say that amongst a magic-user’s emphases, he or she has string and knots. Instead of using strings and/or knots in the description of the spell (though that would be great) I could create an M-U that uses knots to cast any spell. To keep with Swords & Wizardry, a spell’s level is an indicator of the complexity of the knot required to cast the spell. Going even further, the M-U doesn’t need to study spells to re-cast them. He or she simply needs to make more knots. The time requirement is the same to keep from mucking about the mechanics, but instead of hours of study to keep a semi-alive magical thing trapped in the M-U’s mind to be released as a spell, the M-U weaves magical energy into a beautiful and complex knot.

Here are some examples to ponder:

Keeping that in mind, let’s create an NPC wizard with emphases on knots, things that take thread form, red, gold, knots, and two or three more. We’ll call him Zhanguo Jee.

Fast forward a number of years to our party delving into a dungeon and tower that are the remnants of Zhanguo Jee’s tower and lab. There would be encounters with all kinds of crossbred creatures, monsters taking refuge in the tower and dungeon, local dread of the place, and the promise of great reward.

Into this dungeon, we scatter a few knots here and there. Maybe we add in a mad mongerlman M-U that was Zhanguo’s assistant. He goes around muttering gibberish about how it’s all tied up and can’t be untied. Throw in some spiders weaving really really weird webs. Use the M-U’s emphases to create some variant creatures.

This may seem like uneccesary window dressing the the party, but if they find Zhanguo’s spell book and/or scrolls, the party’s M-U has some new spells and a few knots to be able to get started on casting them. The referee could rule that after some study, the party’s M-U can add one or two emphases to be able to cast Zhanguo’s spells. Of course, there would be slight variations as the party’s M-U would not have the same emphases as Zhanguo did, but that’s all the more fun for everyone.

I’ll have to write this up someday.