Blood & Bile: Behind the Design

A couple of weeks ago I released my first PWYW product on DriveThruRPG, a minimalist RPG called Blood & Bile. I've had a few private conversions about the underlying mechanics since then, so I thought it might be worth writing a short blog post on the subject.

System Overview

Each player has five d6s, color-coded to indicate which trait they represent (blue for brawn, green for guile, red for reflexes). The PCs are vampires, so the overall dice pool also indicates how much blood they have remaining.

When you make a trait check, you choose and roll 1-3 of your dice; if the highest die equals or exceeds the difficulty, you succeed. Any dice that color-match the trait can be rerolled once each, and if you invoke an appropriate "asset" you add a +1 bonus to one die.

If you fail a "dangerous" trait check, such as combat, discard the lowest rolling die (representing your body burning blood to regenerate injuries). Furthermore, if you roll a double you also discard one of the dice (representing burning blood for supernatural effort), while on a triple you discard two dice. Discarded dice can be recovered through feeding.

Crunching the Numbers

A character's chance of success depends on the difficulty of the trait check, and the number of dice they roll, as follows:

Although you can only roll a maximum of three dice for a trait check, you are allowed to reroll dice that match the trait, which means those dice each count as two for the purposes of calculating the chance of success. For example, if you roll two red dice and one blue die for a reflexes check, that would be the equivalent of rolling five dice, because the two red dice could be rerolled on a failure.

This means that (for example) rolling one red die for a reflexes check has the same chance of success as rolling two green or blue dice. However the red die has the advantage of not being able to roll a double on its own, while the blue or green dice would have the possibility of achieving two success when making an extended challenge.

Doubles and Triples

There's normally a 16.67% chance of rolling a double with two dice, while rolling three dice has a 41.67% chance of a double and a 2.78% chance of a triple. This might seem very high, however the risk is greatly reduced when rolling dice that match the trait check. For example if you roll two dice for a reflexes check, and one of those dice is red, there's only a 2.78% chance of rolling a double—and if both dice are red, there's only a 0.46% chance of rolling a double.

Although characters don't gain additional dice as they advance, they do earn assets. By invoking an asset to add +1 to one die, you can reduce the chance of rolling a double on two dice (or a triple on three dice) to 0%, and significantly reduce the chance of rolling a double with three dice—particularly if some of the dice also match the trait.

Assets

Assets are a simple mechanic that can represent skills, knowledge, equipment, allies, supernatural abilities, etc. It's best not to choose something too narrowly focused or overly specialized, otherwise it can be difficult to incorporate the asset into the story.

An asset can be invoked to add a +1 bonus to one die, which is the equivalent of lowering the difficulty by 1 (at least for the standard trait checks; extended trait checks track multiple successes). This bonus can also be used to break a double, or turn a triple into a double, which makes "supernatural effort" a far less risky prospect, as mentioned earlier.

Although they can only be invoked once per session each, your assets are always invoked after rolling, which means you only use them in situations where they make a difference. An asset never needs to be "wasted" on a roll where it has no impact on the outcome.

Summary

The game mechanics in Blood & Bile are obviously (intentionally) fairly simple, but I still wanted players to be able to make tactical decisions when rolling the dice, and I think I succeeded in that aim. I initially had doubts about the "asset" rules, but they've grown on me—they are mechanically extremely simple, but they provide the player with some useful options, tie in nicely with the narrative focus of the game, and can cover a wide range of different character abilities.

PWYW: My thoughts after the first week

I've been offering free products through DriveThruRPG for a few months now, but last week I released my first PWYW (Pay What You Want) product, Blood & Bile. In practice this was a very small step (I just had to activate the PWYW option, and enter a suggested price), but it felt like a major personal milestone for me as an indie publisher.

I'm pleased with the way Blood & Bile turned out, but it's a very different style of game to Saga of the Goblin Horde, and incorporates some experimental ideas I wanted to try (such as not requiring any GM preparation, or character sheets for the players) - so I didn't want people buying it blindly based on my earlier work, and then feeling misled afterwards. I was also curious about the PWYW model, and figured this would be a good way to test the waters.

It has been pointed out that PWYW is a marketing strategy rather than a sales strategy, and there have been some interesting discussions (as well as this excellent article) about the pros and cons. My work is well known within the Savage Worlds community, but now I'm trying to establish myself in the wider RPG community, so building up an audience is currently my main priority.

Blood & Bile was released on 14th March. I already had 2696 unique customers on DriveThruRPG thanks to Saga of the Goblin Horde, and 2222 of them accepted email from publishers, so I sent out a short message telling them about my latest product. While that didn't spark quite as much interest as I'd hoped, I did get a reasonable number of downloads in the first couple of days, after which it slowed down to a trickle:

14th March: 70 downloads (including 9 sales totaling $11.20)

15th March: 114 downloads (including 15 sales totaling $33.56)

16th March: 38 downloads (including 5 sales totaling $11.79)

17th March: 20 downloads (including 4 sales totaling $8.00)

18th March: 15 downloads (no sales)

19th March: 19 downloads (including 3 sales totaling $7.00)

20th March: 9 downloads (no sales)

21st March: 4 downloads (including 2 sales totaling $1.01)

That's a total of 289 downloads, of which 38 (13.1%) were sales. The total sales were $72.56, which is an average of $1.89 per paying customer. Nearly half (18 people) paid the recommended $1, the lowest amount was $0.01, and the highest was $5 (paid by 6 different people).

It's the total number of (non-free) sales that determine rankings and medals, rather than the amount of money paid, so even a 1-cent sale is useful. At one point I managed to reach rank 8 in the Hottest Small Press, but there's a lot of competition on there, and I soon dropped back down again.

Ratings and reviews seem to be harder to come by. I had expected people would be more willing to click on a rating than pay money, but that doesn't seem to be the case. So far I've had two reviews, hopefully there will be more once people have had the chance to try out the game.

DriveThruRPG keep 30% of the sales, which leaves me with a little over $50 that I can put towards future products. I'm not yet sure how I'll use that, if there's interest I may release another minimalist RPG using the same system, otherwise I'll probably put it towards Swift d12.

Blood & Bile: My first PWYW product

I'm a fan of both vampire movies and zombie movies, and have occasionally pondered how well a vampire would fare during a zombie apocalypse. So when the guys on the Wild Die Podcast held a One Sheet Setting contest, I decided to submit an entry called "Blood & Brains"!

Of course One Sheet Settings involve quite a bit of work, so to encourage participation, the contest entries were only supposed to give a short overview. But I'd already started writing up my notes by that point, and I had some fairly concrete ideas about how I wanted the setting to look and work, so I ended up submitting a different setting outline (Circus Cult) instead.

But then I got back to working on my vampire/zombie setting, which I'd renamed to "Blood & Bile" after discovering there were already several RPG products called "Blood and Brains" (my second choice, "Flesh & Blood", was taken as well).

As Blood & Bile took shape, I started to feel it would be good enough to turn into a small commercial product, a bit like Just Insert Imagination's awesome plug-and-play settings (such as Fuhgeddaboudit, Punted in the Bonce, etc). But of course that would require changing to a different roleplaying system.

Fortunately I'd recently been pondering alternative applications for the color-coded dice system I'd used in The Goblin Warrens, and this seemed a perfect fit. The mechanics were lightweight and straightforward, intuitive but also tactical, and they would allow me to offer Blood & Brains as a fully self-contained product.

Of course I needed to expand the system slightly, to incorporate unique abilities, character advancement, and so on. I also wanted to playtest the rules before releasing them, but I've finally finished, and here it is!

Download it here: Blood & Bile

It's pretty different to Saga of the Goblin Horde, as I wanted to try out a few new ideas (in particular, while Saga of the Goblin Horde has fairly linear adventures, I wanted Blood & Bile to be a sandbox with no fixed adventure at all). However I'm pleased with the way it's turned out, and I hope others will enjoy it too.

Playing with Savage Worlds

Running Blood & Bile with Savage Worlds is actually pretty straightforward. You could use the vampire race from the Horror Companion, or use Savage Undead to design your own (it doesn't need to be balanced, either, as the PCs are all vampires). There are zombie stats in Savage Worlds Deluxe, but I'd recommend using the Horror Companion if you want to make them more interesting.

The oracle tables would work the same as usual, meaning you could play Savage Worlds without a GM if you wanted to. Assets would be replaced with regular advancement.

Dark Gift

Instead of a "Dark Gift", every PC begins with Arcane Background (Vampirism), which works as follows:

Arcane Background (Vampirism)

Power Points: 10

Arcane Skill: Spirit

Starting Powers: 1

Backlash: None

Available powers: armor*, beast friend, boost/lower trait*, burrow, deflection*, disguise*, fear, fly*, greater healing*, healing*, intangibility*, invisibility, mind reading, puppet, quickness*, shape change (bat or wolf), speed*, wall walker*, warrior's gift*. Those marked with a * have their range reduced to "Self".

The "Power Points" also represent blood; the vampire only regains Power Points by feeding on a human (the same as in Savage Undead), but must also expend a Power Point to wake up each evening.

Curse

The "Curse" would simply be handled through Hindrances. Here are two new Hindrances I'd originally planned to include in the One Sheet Setting:

Carrier (Minor)

Although vampires are immune to the zombie virus, a few of them can become carriers. Any human this character feeds upon directly will become infected, as if they'd been bitten by a zombie.

Marked (Minor or Major)

A zombie took a bite out of this character, and for some unknown reason the wound refuses to heal properly. Any humans who see the bite mark will probably assume the vampire is an infected human, and react with fear or violence. As a Minor Hindrance the mark can be covered with clothing, although paranoid humans may insist on a careful examination. As a Major Hindrance the mark is on an obvious location, such as the hand or neck.

Movie Crossovers

Blood & Bile provides guidelines for defining your own mythology, and one of the suggestions it makes is to combine your favorite vampire movie with your favorite zombie flick. I created a poll on the Savage Worlds Facebook group to ask which movie combos people found appealing, so here are some suggestions based on the top three results.

80s Horror Comedy

Imagine "The Lost Boys" meets "The Return of the Living Dead". The game takes place shortly after The Return of the Living Dead ends, when acid rain from a nuclear exposion spreads the zombie infection far and wide. The PCs are a gang of young vampires, who sleep all day and party all night - until one night the zombies decide to crash the party!

Month of Horror

Imagine "30 Days of Night" meets "28 Days Later". The PCs are vicious vampires, being transported in the hold of a ship. Then one evening they wake up to discover the ship has run aground and been abandoned by the crew. As they leave the ship in search of blood, they find the tables have turned, and they come under attack by hordes of rage-fuelled humans carrying an infection of their own!

Tongue-in-Cheek

Imagine "What We Do in the Shadows" meets "Shaun of the Dead". A group of vampires live together in the basement of the Winchester pub, where they try their best to adapt to modern life. Then one day a zombie outbreak occurs, and when the vampires wake up in the evening, they discover a ragrag crew of survivors have gathered in the pub, while zombies bang on the doors and windows outside!

Other Fiction

When I was googling around to make sure nobody else used the same name, I came across a rather cool story about a vampire experiencing the zombie apocalypse; it's worth a read if you're thinking of running Blood & Bile.

Then when I posted for feedback on the setting, I also received several more suggestions. Darren Miller recommended Double Dead by Chuck Wendig (which I've since read, and enjoyed very much), while Bill Ogden pointed me to the Last Blood web comic (also a good read).

Someone also pointed me to the Vampires vs Zombies Deadliest Warrior episode, which I found quite entertaining (although the Blood & Bile vampires cannot be infected, so you should ignore the ending):

Blood & Bile doesn't define the mythology or physiology of the undead, instead it leaves it up to the reader to decide for themselves, and this makes it very easy to draw on many different sources of inspiration for your games!

Creating a print-ready PDF

In December I provided step-for-step guidelines for printing Saga of the Goblin Horde through Lulu. In this post, I'll show how to prepare your own print-ready PDFs using Scribus. If you're using InDesign or some other desktop publishing software then you'll have to find the equivalent options, and if you're printing through DriveThruRPG you'll have to do further investigation for handling colors, but this should at least get you started.

Cover

For Lulu and DriveThruRPG (and I presume other print-on-demand services) you have to upload covers as separate image files - either one for the front cover and another for the back cover, or a single image for a wraparound cover. You'll have to prepare these images separately, they will need bleed areas, and there may be a maximum file size (for Lulu it's 10 MB). The specifications (and usually image templates) should be provided by the printing company, and will depend on the size of your book, and the type of cover.

The covers should also be removed from the PDF, otherwise they'll be printed again inside the book. But make sure this doesn't change the page numbers, otherwise it may cause confusion when people discuss your book online, and reference certain pages. The approach I used was to replace the cover with a title page for the print-ready PDF; a title page didn't seem necessary for a normal PDF, but it's common in a printed book, and it meant I didn't need to fiddle around with page numbers.

Transparency and Resolution

It seems that print-on-demand cannot print transparent images. If you really need a transparent image (such as the watermarks I use in Saga of the Goblin Horde) you'll need to create a custom background image for it. But the final PDF will need to be flattened, and I found the quickest and easiest way to do this was to set the Compatibility to PDF 1.3 (which doesn't support transparency).

You should also make sure the resolution is correct. For screen use I always set the DPI to 150 (it keeps the file size down without visibility reducing the quality on the screen), but a print-ready PDF it should be set to 300 DPI instead.

Bleed

When a PDF is printed, the pages are not trimmed with 100% accuracy, so it's important to add a bleed area - that means any background and illustrations that normally touch the edge of the page should extend beyond it for a short distance. Lulu requires a bleed area of 0.125" on each side, but other printing companies may be different.

To set up the bleed area in Scribus, press "File" then "Document Setup", and on the "Document" tab you can set your bleeds (note that these are larger than 0.125" in the screenshot below, I'll explain why later):

When you press the "Save as PDF" button, on the "Pre-Press" tab you must also make sure the "Use Document Bleeds" checkbox is checked.

Colors

Print-on-demand uses CMYK, and you'll also need to factor in things like ink coverage, solid blacks, overprint, etc. However this isn't something I've worked with yet, because Lulu prefer you to upload RGB files, so they can convert it themselves. This obviously makes the process much easier if you're using Lulu!

However if you want to generate a CMYK (or grayscale) PDF, you'll need to use the "Color" tab when you "Save as PDF". Make sure you also check the "Convert Spot Colors to Process Colors" checkbox as well, as you won't be using spot colors for print-on-demand.

Margins/Gutter

Saga of the Goblin Horde is US Letter size (8.5x11"), but for printing on Lulu I needed 0.125" bleed on each side, meaning the PDF had to be 8.75x11.25". However when I printed the book I found the text was a little too close to the gutter (the part of the page that connects to the spine), so I increased the page size to 9x11.57" (retaining the same proportions) and then reduced the PDF back down to 8.75x11.25" using a tool called jPDF Tweak. This shrank everything on the page, giving the final print-ready PDF slightly wider margins on all sides.

Note how the page on the right has slightly larger margins.

Open jPDF Tweak. On the "Input" tab, press "Select", choose the PDF you wish to work on (it may take a while to load). You can then press the "Page Size" tab, check the "Scale Pages" checkbox, and set the desired page size (you'll have to convert from inches to points). Then go to "Output" and press "Run".

Once you've generated your new PDF, make sure you open it and scroll through it (on one occasion it corrupted my file, and there was an error when I tried to view the last page). You should also right click on the open file and select "Document Properties", to make sure the dimensions are correct.

The final PDF should now be ready for printing, but make sure you print a sample copy for yourself (so you can check the physical product) before releasing it into the wild. Good luck!