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Really love this supplement you wrote, it's really amazing. One question though, under the class features that say Combat, what exactly does this mean? An example of my quandary is how the Fighter says it advances attacks and saves by two points each level, but when I look at the chart it doesn't look like the saves are advancing that way. Can you help me understand this a bit better?

Thanks for the comment, MxOberon!

Fighters advance both attacks and saves by two points every three levels of experience, not each level. So, in other words, over the course of going from level 1-4, you can see that fighters go from an attack bonus of +1 to +3 (so an improvement of two points), and their saving throw target goes from 14 to 12 (so an improvement of two points).

It's worth saying, I suppose, that actually trying to figure out what your Combat advancement is with a phrase like "two points every four levels of experience" in the middle of a game is messy. The only reason I wrote it out explicitly is that if people wanted to use this model to build other classes, it would give them good guidelines that are balanced but progress faster than purely going by B/X numbers.

Hope this helps! Feel free to ask me any other questions you might have. :3


So this is easily my favorite OSE product I've seen, this is really good stuff!  If you ever make a print version I'd be happy to purchase! 

I am looking to make my own versions of the various Demihuman and Advanced classes for my playgroup with the save and Thac0 progression you use in RBR. Since RBR classes are generally buffed compared to the core classes, I was wondering if you could give me some insight on how/why you buffed across the classes so I could apply that to my own stuff, if that makes sense?  Thanks! 

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The core progression is laid out as transparently as I'm able in the Combat section of each class - a martial class advances in saves/attacks two points every three levels of experience starting at THAC0 18[+1],  clerics and thieves advance two points every four levels of experience starting at THACO 19[+0], and magic-users advance two points every five levels of experience starting at THACO 19[+0].

The decision to start fighter-riffs at 18[+1] was inspired by playing Lamentations of the Flame Princess, where fighters are just noticeably better at fighting even at level 1, before any Experience gets integrated into a character. I think that today's gaming environment (be it 5e or OSR) is so much more focused on pick-up games and short campaigns rather than these multi-year megadungeons from the 1980s that having early differentiation is really important.

You'll note that I adjust languages to not be INT-dependent, but just have them be appropriate for the campaign. I think in general it's silly and culturally reductive to tie languages down so much to class rather than to campaign setting. In our real world, we have societies that have always been multilingual in parts of Europe and the Middle East, as well as societies that basically only have one language. I think fantasy worlds should be free to have that nuance too, without INT-locking.

One thing I do in my design process is that I start all my classes in Excel (or any other spreadsheet program), so that I can compare Experience Curves, Hit Dice, THAC0, and Saves to each other, side-by-side. Spreadsheets are a powerful tool to help me identify patterns, break patterns, and the like. I even do this for base game classes, so that I have a reminder of what each edition of D&D has changed - for instance, did you know that the OD&D magic-user's EXP curve scales completely differently from the B/X magic-user's EXP curve? Seeing trends like that as clearly as possible helps clarify what sort of decision-making you need to make for the final product.

Excel also makes it easy to double-check if my conversions are what I want them to be - you'll notice that I moved all the d100 thief skills to the d20, copying what Adventurer Conqueror King did. I think that this may reduce coherency to new players because it's easier to think in percent than in d20's 5% increment buckets, but it means fewer dice that the player needs to keep track of, which is a plus for me. Anyway, Excel helps me double-check calculations quickly if I need to.

My final note is...just make sure that when you apply a mathematical shift, you apply it as consistently as possible. Example: my Cleric+ class has spells at level 1 (again driven by the fact that our play culture has changed and a lot of people may never level up their cleric in a pick-up game), and I didn't want to just have that single change. I also didn't want to take the Labyrinth Lord approach, where the spell progression is completely changed from B/X to be something more AD&D-inspired. 

So, I wrote out an algorithm for how the base spells for the cleric would improve past L1. I think it was N+ceiling(N/4)? So yeah, doing something like this doesn't make your design more "valid", but it does make it reproducible if you want to build, for instance, multiple classes with whatever your new scaling is compared to the original one.


This is really helpful, thank you!

This is from a year ago now, but I'm curious if you ever ended up creating a product with Demihuman and Advanced classes? If you did, I'd be really interested in seeing the result!


I started to and eventually gave up. There's some remnants in excel format somewhere on my PC for the first couple I put together. Ultimately, I decided to just run vanilla OSE. 


For the thief's new backstab progression how is the damage calculated? Are strength and magic modifiers multiplied or are they added after?

The new backstab progression is inspired from Advanced D&D 1e and OD&D Supplement I, so I'll use those two as the basis of a formal, legalistic answer. On page 27 of the AD&D Player's Handbook, back stabbing is described as follows:

"Back stabbing is the striking of a blow from behind, be it with club, dagger, or sword. The damage done per hit is twice normal for the weapon used per four experience levels of the thief, i.e. double damage at levels 1-4, triple at 5-8, quadruple at levels 9-12, and quintuple at levels 13-16. Note that striking by surprising from behind also increases the hit probability by 20% (+4 on the thief's "to hit" die roll)."

Whereas in Supplement I:

"By striking silently from behind the thief gains two advantages: First, he increases the chance to hit by 20% (+4 on his die). Secondly, he does double damage when he so attacks, with like additional damage for every four levels he has attained. Thus, if a thief of the 4th level attacked from behind he would do twice the damage indicated by the die, at 5th through 8th levels he would do thrice the damage, at 9th through 12th levels he would do four times the damage and so on."

My understanding then is that you would multiply only "the damage indicated by the die", and then apply modifiers afterward, legalistically.

However, I have encountered GMs both old and young who run it as "calculate damage as you would normally, then multiply", and even GMs who include magical modifiers.

Ultimately, due to how risky the backstab maneuver is and how rare it is that players will opt to take the risk, I personally prefer to rule it in that method - with all modifiers applied first, then multiplication, for the greatest possible damage.

I don't think this is supported by the rules-as-written.
But this is the OSR! We do things as we like, and I encourage you to experiment and adjust to the taste of your own players :3