House Rules for d20

There’s a lot of things that I like about the d20 system – the amount of granularity makes it so that there can be a LOT of customization for how a character is portrayed. I’ve had a lot of fun playing and (mostly) running it, from 3.0 to 3.5, Modern, Saga, Pathfinder, and numerous other incarnations.

Still, there were things that bothered me about it, and so I’ve tinkered with it in multiple ways over the years. Many of these changes I started implementing since my 3.0 campaign the “Frozen North”. With my home group deciding to start a campaign of Rise of the Runelords, I decided to codfiy them, and throw in all of the house rules that I’ve been using, as well as the ones I’d been planning and working on. For those that are interested, here are the major changes that I am utilizing (with probably numerous small changes)!

First, the design thoughts behind how I like using house rules:

1. Maintain as much compatability with the base rules as possible. This allows the use of as much published material as possible without heavy conversion. As time is the scarcest resource for me now, this is a major consideration.
2. Return to a grittier, deadlier feel for the d20 system. With a d20 roll and bonus that range from +1 to +10 (at even fairly low levels), the game can be quite “swingy” with skill not playing much of a roll.

The Base Rules:

1. The standard roll is NOT a d20! (Yes, for a d20 system, this is huge!). Instead, all d20 rolls (other than things like random encounters, etc) utilize 2d12.
1. I like a bell curve much more than the linear one of a single die.
2. Why not 2d10?
1. I like 12-siders… just cool looking, well balanced, and fun to roll. These are my favorite dice. Also a d12 is a true polyhedral unlike a d10.
2. The probabilities at the higher end (15+) match closer to 2d12. The effect is low DC tasks are easier to accomplish, and high DC tasks are about the same.
3. HOWEVER, the target numbers are also fluid; ie. specific examples are…
2. Base numbers for opposed rolls are not a fixed 10, but 2d12.
1. In melee, the defender is also active in rolling. A base AC is no longer fixed 10, but an opposed roll from the defender of 2d12 as well.
2. Saving throws are not 10 + modifer, but rather, 2d12 + modifier
3. Degrees of success improve the outcome. For every 10 above the needed target number, there is another “level” of success.
1. In combat, that means for every level of success, there is additional damage dealt equal to the base weapon damage (ie. 10 above needed number with a longsword does 2d8 + modifiers.) Damage from these additional levels of success are not multiplied in a successful critical hit.

Additional rules:

1. More hit points
1. All creatures start with an additional number of hit points equal to Constitution score (times a size modifier.)
1. Medium sized hit point modifier is 1. Small is 0.5. Large is 2, Huge is 4, Gargantuan is 8.
2. This makes large creatures much tougher.
2. Death and Dying. Death does not occur at -10 hp.
1. At 0 hp or below, a character is staggered.
2. At negative hp, all actions have a penalty = the hp. (ie. a PC at -8 hp has a -8 to rolls.)
3. At the start of the character’s initiative, a roll is required to see if the character can stay concious. This is a Fort or Will save vs. DC 2d12 – note, the hp penalty applies to this roll!
4. In most D&D 3.x games, death of a PC is not a major hinderance, if anything, is is more of a monetary penalty than anything else. As such, I wanted to have a gradation of that.
1. At negative hp equal to Con score, 1d6 ability scores are damaged by 1 point.
2. In addition, at negative hp equal to twice Con score, gain 1 temporary negative level (daily save Fort vs DC 2d12).
3. In addition, at negative hp equal to 3x Con score, 1d6 ability scores are drained 1 point (needs restoration spell).
4. In addition, at negative hp equal to 4x Con score, gain 1 permanent negative level (needs restoration spell).
5. In addition, at negative hp equal to 5x Con score, death.
2. More dynamic combat
1. Attacks and defense are related. Will use a dice pool mechanic: Instead of standard 2d12 for attack and 2d12 for defense, a character may allocate 4d12 between attack and defense. This decision persists until the character’s next attack.
1. Attack:
1. The number of attack dice are the same for each of multiple attacks (ie. 2-weapon fighter)
2. NO interative attacks. For each additional iterative attack listed, the character gains an additional d12
3. If more than 2d12 used for attack, two of the dice are designated as the primary attack dice, and used to determine if an attack is a crit. There is no chance of a crit if only attacking with 1d12.
2. Defense: Facing of characters matter.
1. All defense dice can be used for each attack coming from the front facing.
2. All defense dice minus 1 are used for attacks coming from the flanks. A shield’s defense bonus can be used against attacks coming from the shield’s side.
3. All defense dice minus 2 are used for attacks coming from the rear. A shield cannot be used against rear attacks.
4. An unaware defender (ie. attacker successfully snuck up) gets no dice, nor Dex nor shield bonus against an attack.
3. Ranged:
2. Armor and shields
1. Shield defense bonuses are higher:
1. Buckler grants +2, small shield +4, medium +6, large +8
2. Armor grants DR equal to the AC against physical attacks.
1. Armor grants a penalty to Defense = Armor Check Penalty
2. An attacker can attemp to bypass the armor DR by attacking at a penalty equal to the DR (ie. armor works as AC modifier like standard d20).

Flavor rules:

1. Races:
1. Humans: Humans are to be the majority of the races in the world, so I wanted a compelling reason for players to choose playing them.
1. Gain an additional +2 bonus to a seoncd ability score
2. Gain Hero Points at double the rate. Can have maximum of twice the number of Hero Points
2. Hero Points:
1. The Hero Points rule will be used. PCs gain one Hero Point per level gained while playing the PC (a new PC who joins in the game at level 5 only has one Hero Point).