My (and Prof. DM) OSR RPG system, rules and power lite, fast and easy

I have been brooding on, and experimenting with, my own rpg rules since I was 13 and the last few years and especially months it all finally clicked. Due to reading OSR products as well as watching Youtube videos. Yesterday I tried out my own system and character record sheet for first time and I don’t think I will ever go back. I am writing up the rules to share with others but might take a bit before they are properly done. I also commissioned a character record sheet which the designer did a truly great job on, I will open source/share that in a few weeks.

Rules / how I play:

  1. No initiative, essentially everything happens at once with a few exceptions, I used a 60 second hour glass/sand timer, during those 60 seconds all my players have to tell me what they are doing and they can not change it. Every round still represents 6 seconds. See this video for the finer points and how things resolve:

I wish I had played like this since day one, it truly speeds up and simplifies combat tremendously, which in turn makes it far more exciting/scary and chaotic in a good way, imo all this is far more realistic. It also frees up way more session time for either new battles or for what I prefer: more role-playing and collaborative world-building. I prefer to, on average, spending half of each session or a bit less on combat.

  1. Magic I have discussed in another topic on this forum. Essentially: players have to find or be taught or be granted (deity) spells except the first few most common and basic spells. No spell table. There is a spell “attack” roll, with the DC going up if player casts more spells within a short time frame or repeats a spell, if the first d20 “attack” roll hits my DC/AC/Target number then a second d20 roll is made to see how effective the spell is. I vary effects and dmg according to this second roll. Critical misses or hits are possible. If the first roll is not a 1. but just below my target number, the spell simply fizzles with no ill effects.

Extremely short and simplified spell list and descriptions, the spell level of each spell corresponds with the character level. A 5th level Wizard can cast 5th level spell, subject to the rolls and stipulations above. Any overpowered spells simply are moved a level or more up. Potentially game changing or breaking spells will have a very high DC or require rare and expensive magical components that are consumed, irregardless that the Wizard has the required (same) level to cast these spells.

  1. Low power level, but that goes for both players and the monsters and NPCs. Fighter has Hit Dice 1d8 and does 1d8 damage with any weapon he uses. Thief / Cleric use 1d6 for both, Wizard 1d4. In order for my Wizard to have survive ability I will grant him a “Ghost hit point” and “Shield” type spell next session, both spells only very temporarily grant a few extra hit points or AC bonus. Characters do get their maximum hit die at first level and there is a Con bonus.

Dex bonus adjusts Attack bonus for ranged weapons, but not damage, Str bonus adjusts both attack bonus and damage, this is to make sure the fighter stays balanced/useful, including at higher levels. Characters can only do one spell, thing or attack per round, but in a few levels the fighter will get the ability to spread damage over 2 opponents and a few other such tweaks that make his melee attacks more powerful, versatile and useful without requiring more rolls or slowing down the game.

  1. Only Fighters can wear armor that grants AC 14 or above without it affecting their core competencies, magic users and thieves will be negatively affected when using their special class specific skills if they are wearing heavier armor types.

  2. Anyone can use any weapon (subject to the info at 3.), but within reason: a halfling will have issues and penalties with a halberd, if a player picks up a weapon they are very unfamiliar with (emergency) I will very likely raise their target number needed for a successful attack.

  3. I am not using saving throws at the moment since I decide damage/dice for every spell anyway, depending on circumstance, rolls, level of the caster or the target etc. I am still on the fence whether I should have saving throws, perhaps for poison and such it is necessary.

  4. I use the “themed room” approach of Index Card RPG: for simplicity’s sake and fast play, every tasks or enemy in most (not all!) rooms or areas have the same challenge rating/AC/DC.

I do use Awesome points (=inspiration) as well as Advantage / Disadvantage and I give bonuses or penalties to rolls when people roleplay well, or describe things well, have a clever plan etc.

Of course in pivotal battles or if there is a boss type character I adjust ACs and DCs, but in most situations it is a huge time saver and much clearer and less confusing for myself as well as players that they know exactly how hard an encounter or area is from the get go using the themed room approach. As Prof DM notes, this approach also really solves scalability problems at higher level and makes combat with quite a enemies easier to run and resolve.

  1. For character generation I use the: 4d6, drop the lowers die result and players assign these scores freely to any of the 6 abilities method. However, after rolling I do add up/subtract the bonus results and make sure everyone has the same net bonus. This means there is plenty of variability and some randomness to the stats of characters, yet their power levels are ball park commensurate, not overpowered and players have more than enough choice to play any class or type of character they want.

  2. Starting equipment and money is extremely limited on purpose. 6 Cp each, one weapon and 1 or 2 -no more- very basic tools of their trade/class, no armor except the fighter who has basic leather armour. I found this instantly made them want to find jobs/quests of any kind, made them bond or share quicker, gave them many small but clear intrinsic goals and allowed us to dive into the game faster. It also makes the early game very challenging but rewarding.

  3. I made and use the “Ultimate Dungeon Terrain” which highly simplifies ranges and visualization during battles.

All the above means, I adjudicate, decide a lot of target numbers and outcomes using a simple d20 system where every task is between 1 and 20 in DC. No DC 27 in this game. My system does require plenty of fair and informed GM decisions and being reasonable but, I find that faaaar easier to do rather than know, partially remember and interpret/apply complicated and long rules that differ for many situations and every spell. This system would not be suitable for people who love spells or rules to be extremely predictable, or for GMs who do not want to decide a fair amount on the fly, nor for power-players who like high stats or multiple, stacking high bonuses and more rather than less rules.

I will certainly still tweak some things, yet so far, most enjoyable to run session I have ever played and the players all very much enjoyed it too. We didn’t look at the 5e PHB rules or even my own written rules at all once we build characters together, which was at least 3 times as fast as building a 5e character. We roleplayed a ton. I do allow subclasses but I make sure that any game mechanical advantages these classes have are mirrored by having some disadvantages, a Ranger would be far better at wilderness survival and tracking checks for instance but do worse in cities with the different type checks that are required there.

I focus a lot on Archetypes however: a Foodie or Cook is a kind of Archetype, Pig farmer, Knife collector, Han Solo like swashbuckler, Socially awkward but kind-hearted soul, (wannabe/starting) Assassin, Bookwurm that wants to see the world and 1000s more are all possible archetypes. Players are free to choose pretty much any Archetype, in order to create RPG opportunities and to distinguish them from the other characters, regardless of class. I do translate these into some fairly rare small bonuses that can ramp up if a character reaches 5th level. If every character has an archetype, these bonuses balance out fairly well.

Next sesh I am also implementing a very simple skills system, all it does is allow characters to get a +1 if they get pick a skill and if they specialize in it a +2 bonus on certain checks, lets say a voracious reader, bookwurm character tries a general knowledge or history check she will get the bonus on the attempt while a character who is good at hunting and butchering would not etc.

Thoughts? :slight_smile:


I like the diegetic magic system. Makes the wizard involved in searching for spells that they need/want. You can make a lot of adventure hooks with that premise.
Archetypes are a cool idea to facilitate roleplay (giving awesome points for building your character around the archetype for example.)
One nitpick though is that cleric, thief and fighter have the same 1d8 HD? Maybe the thief/cleric should have d6 so that they are like a balance between fighter and wizard.

P.S. What a coincidence. I have been developing a character sheet this past week.:wink:

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Hey Max, that was totally a typo, thief and cleric have 1d6 HD as well as Attk Dmg, while Fighter has 1d8. Also, please post your character record sheet when it is done! I paid my designer guy €30 Euros (he was going to do it for €20 but I tipped/felt I should pay more) to make, and tbh even at €30 I think that was a steal, he made 3+ revisions based on what I suggested and spend at least 4 hours on it. I am looking forward to sharing it with community once I have made some tiny last changes.

An chance we might get a looksee at this?

I too have developed a streamlined OSE system I have playtested a few times that I have enjoyed and magic is the one stumper for me. I have been thinking about the caster level = spell level thing but the task to convert the existing spells seems daunting!

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Of course! But I have only just begun, have done almost nothing in writing, mostly in my head. As soon as I have something more substantial I will post it. :slight_smile:

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One of my favorite things about ICRPG is the Room DC concept. I especially like how the Easy/Hard works. Basically, let’s say you have a room full of orcs. They all are wearing similar armor and are experienced combat. You can the Room DC to say 12 to represent this. But, let’s assume there’s also an Orc chief, who is old and wise and wears the best armor in his clan. If one of the players tries to attack him, I’d call for a HARD roll (which adds +3 to the Room DC). Or maybe the chief is an old wizard hanging to his last breaths. Attacking him would be an EASY roll (which subtracts -3 from the Room DC). I find it greatly simplifies combat, and is very easy to wrap your head around.


The Room DC concept is actually the thing that turned me off of ICRPG. I get that it makes it easier to run and in fact, looking at how I run even OSE games, I have noted that I unintentionally do this for my encounters. However, I do not like the idea of showing the players the Room DC, even if I am unintentionally doing it in my mind. Just feels too much like letting the players see behind the curtain for me.


Hmm, I had never looked at it that way. But to me the room DC is a bit like AC. You usually tell your players what AC they need in order to hit, or if you don’t they either figure it out, or if not the excitement of just (not) making their roll is suspended. If they have to ask you if they hit or succeed every time before and possibly even after the roll, that is no fun. It is cool for them to know: “I have! to roll XX now, and if not, I know I failed…!”

I supplement my Room/Area DC with disadvantage/advantage mechanic or the “hard” and “easy” bonus/penalty (+2 / -2, I am experimenting with that over +3 and - 3 to not be so close mechanically to the (dis)advantage rule, still not sure on this). That allows me to scale the Room DC in those rare cases when it seems important or fun. Yet sticking to the room DC 75% of the time still provides very fast, easy and more clear play than not using it, by far. Example: Let’s say I tell them the room DC is 15. So the AC of these 3 Gnolls in the room, picking the door lock, sneaking up on the Gnolls, all of it is 15.

There are also simple and easy explanations why this room with Gnolls might be a 15 while another room that also has 3 (different) Gnolls would be a 13. AC 15 Room/Gnolls are older and have been in many battles, or they have armor, they have been in this chamber longer, so they know it well, they happen to be quiet when the players try to sneak up rather than half-asleep/drunk etc etc.

Yet in the example above, while everything would be a 15, once the battle is over, it is the easiest thing in the world for me to say "it appears the Gnolls somehow acquired a chest with a Dwarven lock,… it is Hard to pick = +2 = 17. You will either have to make 17 on your pick lock attempt or open it some other way (find the key, magic etc).

In that sense the room DC can be as simple and fast as you need it to be while also extremely flexible at any specific point in time. The players can imagine themselves why these Gnolls are chamber are tough, you can! narrate as well to convey this, but you do not have to, showing them the room DC does that for you.

As others have argued, it really solves the scalability and having to track or make-up so many stats issues that systems that do not use room DC tend to always have. Another example: whether your PCs are 1st, 3rd of even 7th level, potentially you could still have a room of 4 Orcs be a real challenge by changing the DC, no more of the “I can’t effectively use these type of monsters after a certain level or I have to throw 20! of them at players making for looooong and confusing combat” choices the GM has to make. You no longer need to throw bigger, badder, weirder and more rare monsters at your player every session to create challenge.

Of course at a certain point you do need to narrate. If 7th level characters are going to be challenged by 4 Orcs, you should probably include and quickly describe a Shaman, an experienced leader and two large, older, quite disciplined, experienced fighters that have scavenged some decent armor and weapons. Perhaps they have been in this lair for a long time and dealt with adventurers before, so they have the place set up in such a way to favour them in combat. In these circumstances a DC 18 for 7th level characters against Orcs would make sense, the Orcs being used to fighting together, using tactics, magic etc explains why they are all relatively hard to hit. With their 7th level to hit bonus and magic, the players would still have a very good chance to win the battle, but it would not be a foregone conclusion.

In some way this all is quite in keeping with they early editions of DnD and how Gygax and Arneson played, they always sought to challenge their players, the monstrous manual and the stats within were not supposed to be read much less memorized by the players and those stats, like any rule were more of a guideline or average rather than a static absolute. Even in the monstrous manuals many single/the same monsters would have variants with higher stats based on subraces, being older/a leader type, a variant etc. Room AC essentially does the same but makes it faster and apply not only to the combat modifiers, but to the entire room, unless that is not expedient for the GM. I would not use Room AC in a really important battle/final location that comes up maybe every 4 sessions or so, but for more “average” battles or situations, it works for me.

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I agree fully. Last fall I was really digging into the old/original styles of the game and it led to me streamlining my DMing a great deal. Like I said, I am subconsciously doing this but I still don’t ‘feel right’ putting a big red die out there with the Room DC on it. Silly hang up, but there it is. :slight_smile:

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Funny, I literally! have a huge red die I use for this stuff. But yeh it still feels alien to use it, and easy to forget, since I have done it only 3 sessions now and many dozens of sessions before it wasn’t even something I would ever consider. Old habits die hard hehe. In a weird way it might even seem more fair to the players. The die and mostly static nature the number I choose is super clear, while if I pull every DC out of my rear for literally every ability score check or individual AC, it seems more arbitrary.

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My players never know if it is arbitrary, just keep saying it with a straight face. :slight_smile:

I actually prefer less gradual steps of difficulty when it comes to D&D-esque systems.

In Melan’s Sword & Magic, for instance, everything is rolled against DC 12 (except those denoted as Hard, because that’s DC 18) - and virtually that’s all you need (there’s technically Easy DC 6 and Herculean DC 24, but they rarely if ever come up).

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