So I was challenged by someone else in the forum to just write up my own homebrew since I Have so many problems with the core system. This thread will be where I brainstorm those ideas for home brewing a system based on the new dark heresy.

Goals:

-Create a system that promotes the themes of dark heresy as I see them: grim darkness, suspicion, investigation, over the top combat, grittiness, and black comedy

-create a basic core resolution system that is quick to pick up but offers a degree of granularity

-create a combat system that promotes tactics, over the top results, and tough decisions

-create a social system that has mechanical backing and is fun to play while my interfering with roleplay

-create an investigation system that gives structure to what a game session is meant to play like while being flexible to the dfferent missions that acolytes face

-streamline and consolidate skills and talents to make them simpler but still allow character customization

-create a fun and thematic psychic power system

-make fun rules for vehicles

-have thematic character creation focusing on creating unique characters

-have guidelines for converting existing rules to this system, particularly NPCs and equipment

So that's a lot of stuff. First, I'll throw out the idea that made me decide to start this thread. Lots of people like the d100 system in dark heresy. I personally dislike it both because is based around hunting for modifiers in order to succeed, and the huge amount of swing to rolls and lack of a bell curve mean that the average session's worth of rolls is extremely unlikely to approach the actual probability of the dice and instead produce lots of outliers.

So, I have an idea to take the basic idea of rolling 2d10. One of the d10s represents your attribute, ranging from 1-10. The other d10 represents your skill, also ranging from 1-10. Attributes are range from 2-5 based on human ability. This could be increases by creatures of greater size, or by unnatural attributes. Skills range from 1-3 or 0 for untrained. Your total skill rating is equal to your skill ranks plus your related attribute. So if you have strength 4 and athletics 2, your skill rating is 6.

To resolve a roll, you roll 1d10 for yor attribute and 1d10 for your skill. If you roll equal to or under the rating, that is a a success. There are five kinds of outcomes for your roll.

Complete success: If your attribute and skill roll both succeed, you get a full success with no issue. The various skills will all list examples of complete successes, but this basically means you do what you wanted to do without anything bad happening.

Limited success: if only one of either your attribute or skill roll succeed, you have a limited success. You aucceed at what you wanted to do, but there is either a price to pay or what you did is limited in scope.

Failure: if neither roll succeeds, you fail at what you were attempting and the GM can choose to introduce either grimness or darkness to your characters life. Examples of grimness are things like encroaching insanity, broken technology, or physical injury. Examples of darkness are encroaching corruption, new enemies appearing, or the environment turning against you.

Righteous Success: if both rolls succeed and are equal to each other, you have a righteous success allowing you to do something extraordinarily well or with extra benefits. As a note, if you roll equal numbers and only one success, you may count the roll as a Full Success instead.

Debilitating failure: if you fail and roll doubles, you have a debilitating failure. The GM can introduce grim darkness to your characters life, which include combinations of grimness and darkness or over the top versions of them.

Something you may be wondering is how guns will be handled. Weapon skill and ballistic skill will still be attributes, but instead of having skills for the weapons, the weapons themselves will have reliability modifiers that add to the skill roll. So a lasgun with reliability 2 shot by someone with 4 ballistic skill will have a skill rating of 6.

And what about the modifiers? Well, I'm borrowing a page from the new D&D and using the advantage/disadvantage mechanic. If you have advantageous modifiers in combat, you roll 2 dice for your lowest of skill or attribute and choose the lowest of those to apply to your roll. If you have bad modifiers, you have disadvantage and roll two dice for your lowest of skill or attribute and choose the higher result. So if you have attribute 4 and skill 5, you'd roll two dice for the attribute and one for the skill. Some game mechanics may actually provide penalties to your skill, causing it to be lower than your attribute. If you have a mix of advantage and disadvantage, there is no change to your roll.

What happens if a skill goes above 10? It automatically counts as a success. The due is still rolled to check for doubles. What happens if a skill AND attribute go above 10. Both dice automatically succeed. This feat is normally impossible for humans but may occur for some NPCs. The grim dark future is a scary place. They still roll to check for doubles.

So that's my baseline idea for the system. It's currently cribbing a lot from dungeon world in terms of having partial successes. I'll also be adding what successes mean for each skill, as well as a list if grim, dark, and grimdark moves the GM can inflict on players.

Any thoughts or comments so far?

I really like the idea of Grimness and Darkness being game mechanics.

I am confused about this bit: "As a note, if you roll equal numbers and only one success, you may count the roll as a Full Success instead." Aren't both d10s rolling against the same target number? How is it possible to roll doubles and have only one success?

From what I've followed of D&D5 I understand the advantage/disadvantage mechanic has some funny effects on the math. Have you worked out the probabilities? What's the difference between adding disadvantage and lowering the target number by 1, for example?

One theme of the original Dark Heresy you don't call out is the inevitability of madness and/or corruption (or gruesome death by unlucky dice rolls in combat). As an Inquisitorial acolyte you know you're basically living on borrowed time until your luck runs out - nobody retires from this line of work. Did you choose to drop this theme?

I'm that forum user.

One theme of the original Dark Heresy you don't call out is the inevitability of madness and/or corruption (or gruesome death by unlucky dice rolls in combat). As an Inquisitorial acolyte you know you're basically living on borrowed time until your luck runs out - nobody retires from this line of work. Did you choose to drop this theme?

I have a feeling he might factor this under Grimness and Darkness, as possible failure effects to various situational tests?

I really like the idea of Grimness and Darkness being game mechanics.

I am confused about this bit: "As a note, if you roll equal numbers and only one success, you may count the roll as a Full Success instead." Aren't both d10s rolling against the same target number? How is it possible to roll doubles and have only one success?

From what I've followed of D&D5 I understand the advantage/disadvantage mechanic has some funny effects on the math. Have you worked out the probabilities? What's the difference between adding disadvantage and lowering the target number by 1, for example?

One theme of the original Dark Heresy you don't call out is the inevitability of madness and/or corruption (or gruesome death by unlucky dice rolls in combat). As an Inquisitorial acolyte you know you're basically living on borrowed time until your luck runs out - nobody retires from this line of work. Did you choose to drop this theme?

The attribute d10 rolls against a TN equal to the attribute. The skill d10 rolls against a TN equal to the the skill PLUS the attribute. This is subject to chane as I run the numbers. I'm trying to keep attributes between 2 and 6 for PCs, with skills adding something like 0-4. Running the numbers is slow work as I have failed at creating adequate formulas in excel and hae had to just create massive results tables and count how many of each kind of result occurs.

I've only gotten to run the numbers on advantage for one table so far (attribute of 2, skill of 0), but it was worth the equivalent of increasing the skill by 1.5. This benefit may scale up for higher attributes; I will have to run the numbers to see.

Also, I do plan on having there be some brutal injuries, insanities, and corruption going on. My plan is for characters to never become unplayable, but instead become terribly flawed.

I was thinking of having a corruption/sanity mechanic with players having a stat for each chaos god, and one stat for faith. I was thinking a fun meta game could be to have certain player actions result in their characters becoming more corrupt. When a player acts like a coward to save his own skin, he gets a point for Nurgle. When a player acts like a Murderhobo he gets a point for Khorne. When a player comes up with a really convoluted way to get a bonus, or tries stretching the use of a skill, he gains a tzeench point. When a player makes everyone in the group bust out laughing, he gains a slaanesh point.

Just to be sure, one roll is "Attribute" and the other is "Attribute + Skill"?

I think I can see the reasoning behind that (a chance of success even when not having the skill), but it feels kind of unintuitive if one die is supposed to represent Attribute and the other Skill. As if the "Attribute only" roll would be redundant, when it is already included in the other.

Perhaps you could instead increase the range of "skill levels", and have a character start out with a minimum of 3 once they learn something?

This might also allow for a better representation of a character with little to zero knowledge trying it anyways, if you allow people to roll on appropriate tasks with a 1, meaning a 10% chance to succeed by simple luck, not counting the separate Attribute roll. For more difficult/complicated tasks attempted by untrained characters you could rule that limited successes are not possible and both rolls must succeed in order to evoke any positive effect.

Furthermore, this approach greatly expands the range of Reliability Ratings you can apply to the different weapons.

Example #1: Trooper Ferk (Agility 4) attempts to shoot a bow. As he lacks proper training with this sort of weapon, he has to roll two d10 against 4 (Attribute) and 1 (No Reliability applies) in order to hit the target. A complete success might mean an impressive shot, whilst limited success means he at least hit his target *somewhere*.

Example #2: Trooper Ferk (Intelligence 3) is now trying to access an unencrypted data repositorium. Since he has never worked with cogitators before, he has to roll against 3 (Attribute) and 1 (Untrained) - however, unlike shooting a bow this is a much more complicated task with more that can go wrong, a limited success is not possible. He will either succeed in locating the data he is looking for, or (more likely) trigger an alarm.

Just a thought that popped up in my head, mind you. Personally, I think I prefer the d100 system, or Dragon Age's 3d6, but I have a feeling you are going for something like FFG's Star Wars RPG here, with a greater focus on narrative effects?

Anyways, it's an interesting enterprise - good luck!

One theme of the original Dark Heresy you don't call out is the inevitability of madness and/or corruption (or gruesome death by unlucky dice rolls in combat). As an Inquisitorial acolyte you know you're basically living on borrowed time until your luck runs out - nobody retires from this line of work. Did you choose to drop this theme?

I have a feeling he might factor this under Grimness and Darkness, as possible failure effects to various situational tests?

Well, if you attempt an untrained basic skill, you'd roll 2d10, with both TNs being equal to your attribute. I was thinking for advanced skills or weapons, you'd automatically roll at a disadvantage for them if you're untrained.

Well now I'm more confused. In your first post you say the resolution mechanic is rolling 2d10. That's not the same as rolling 1d10 twice, which seems to be what you're saying with having different target numbers. In my opinion, you should find a way to keep any test to only one roll.

For dice probability, have you tried anydice.com?

Well, if you attempt an untrained basic skill, you'd roll 2d10, with both TNs being equal to your attribute. I was thinking for advanced skills or weapons, you'd automatically roll at a disadvantage for them if you're untrained.

Gotcha - though, isn't this still fairly generous, considering that the player sacrifices only 1/3 of their chance on a single die, for effectively knowing "jack ****" about what they're actually trying to do?

The advantage/disadvantage mechanic with rolling additional dice seems a bit convoluted to me considering you were trying to simplify the game (or were you?) ... but this could merely be a matter of perception and preferences.

Well now I'm more confused. In your first post you say the resolution mechanic is rolling 2d10. That's not the same as rolling 1d10 twice, which seems to be what you're saying with having different target numbers. In my opinion, you should find a way to keep any test to only one roll.

For dice probability, have you tried anydice.com?

Well, it's 2d10 in the same way that d100 is 2d10. One of the d10s should be a different color or something to differentiate it from the other.

I tried any dice, but I have no programming experience so it's beyond me how to program my dice system into it

So I've run the numbers more fully, and I really don't like what I'm seeing. Things aren't scaling linearly. I'm going to rework the core mechanic to try to get something with better math. I'll keep people posted.

So I've run the numbers more fully, and I really don't like what I'm seeing. Things aren't scaling linearly. I'm going to rework the core mechanic to try to get something with better math. I'll keep people posted.

Lack of linearity isn't necessarily bad, if you ask me. Another System I used to play uses a 2D10 Roll Under System. Essentially you add Attribute and Skill (each has a Maximum of 10) and have to roll under with 2D10 (added, of course).

Leads to the interesting scaling that you first improve very slowly, then improving faster (percentage-wise) and everything above 12 is really luxury. And when a test becomes more difficult, it "cuts" the numbers from the bottom, introducing both an upper and a lower threshold.

I'm still looking at things, but the thing really messing with the math are the rules on doubles. I'm looking into how to fix this.