House Rules for upcoming D&D 5E campaign

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Following up on my post on building a set of D&D* house rules, here are the current rules that I want to use, along with their intended purpose. The overall guiding principle is that I want players to consider combat as a dangerous, unpredictable, and costly option.

Table of Contents

  • Ability Checks
  • Aftermath of Combat
  • Conversation Reaction
  • Exploding Criticals
  • Firing into Melee
  • Hazard System (Time Management)
  • Healing and Recovery - pending; Slowed recovery times
  • Life Drain - pending; Based on 5E* but slower recovery
  • Loyalty - pending; Based on 5E DMG*
  • Massive Damage
  • Morale
  • Missile Fire While in Melee - pending
  • Pushing Spellcasting - pending; Rolemaster and Burning Wheel inspired
  • Ritual Magic
  • Scripted Combat - pending; Inspired by BWG*2E* yet cribbed from 5E DMG
  • Spellcasting While in Melee - pending
  • Where We Last Left Off

Ability Checks

When you fail an ability check, you may choose to succeed at cost. If you fail by more than 5, choosing success will come at a major cost.

Aftermath of Combat

After any combat, each character that engaged in combat must either:

  • Spend a turn resting
  • Ignore resting, making a Constitution save (DC* 8 + number of rounds of combat) or gain one level of exhaustion.

While spending a turn resting, a character may:

  • Spend one (1) hit die to regain hit points
  • Cast non-ritual spells
  • Perform other non-strenuous activity

Conversation Reaction

Not all encounters need start with drawing swords. If characters choose to engage in a conversation, the GM* will determine their starting disposition – friendly, indifferent, or hostile.

Once the players get to the point of their request or demand roll the applicable Charisma (perception, persuasion, or intimidation) check as applicable. Then consult the table for the response.

Table 37: Extracted from the 5E Dungeon Master’s Guide p244
DC Friendly Indifferent Hostile
0 Do it if no risk/cost No help nor harm Opposes action might take risk
10 Do it will accept minor risk/cost Do it if no risk/cost No help nor harm
20 Do it will accept major risk/cost Do it will accept minor risk/cost Do it if no risk/cost

Exploding Criticals (Old House Rule)

When you roll a critical hit, roll your attack again and increase your critical hit range by 1. If this would be a critical hit, roll again and increase the range again by 1, and so on. Once your roll is not a critical hit, the number of critical hits you achieved is the number of extra times you roll damage.

Example: Fath, an elf fighter, wielding his longsword (d8+3) is attacking an ogre. He rolls a 20 on his attack. A critical hit. Fath needs to see if his critical explodes; He’ll need a 19 or 20 to continue exploding; The roll is a 19. Fath’s player grabs the die and rolls again; This time he’ll need an 18, 19 or 20. He rolls an 17. So close.

Fath’s final damage roll is 3d8+3; one die for base damage, one for the critical, and one for the first explosion.

Firing into Melee (Inspired by DMG 2E* Revised p132)

When firing into a melee, any attack that requires a to hit roll might hit unintended targets. Count the target of the attack and any potential targets adjacent to the intended target.

For each target determine their chance value, doubling the chance for the intended target. Then randomly determine which target is hit based on the weighted chance.

Table 38: Firing into Melee
Target Size Chance Value
Tiny 1/4
Small 1/2
Medium 1
Large 2
Huge 4
Gargantuan 8
An attacker may take a -5 to their to hit roll to avoid any chance of hitting an unintended target.

Hazard System

I will be using the Brendan S’s Hazard System; Though perhaps with a few adjustments.


An injury occurs when you…

  • Drop to 0 hit points but aren’t killed outright.
  • Fail a death saving throw by 5 or more.

See page 272 of the DMG for the chart.

Massive Damage

If you take half of your maximum hit points (or more) in a single attack, you must succeed at a DC 15 Constitution save or suffer system shock (see DMG p273). If you fail your save by 5 or more, roll system shock with disadvantage.

Table 39: Transcribed from the 5e Dungeon Master’s Guide p273
d10 Effect
1 Creature drops to 0 hit points.
2-3 Creature drops to 0 hit points but is stable.
4-5 Creature is stunned until the end of its next turn.
6-7 Creature can't take reactions and has disadvantage on attack rolls and ability checks until the end of its next turn.
8-10 The creature can't take reactions until the end of its next turn.


Creatures might flee if…

  • Surprised
  • When reduced to 1/2 its hit points or fewer (for the first time in the battle)
  • Has no way to harm opposition

Group might flee if…

  • All are surprised
  • Group’s leader is incapacitated, killed, captured, or removed from the battle
  • Group is reduced to half its original size with no losses on opposing side.

Check morale by having the creature or group leader make a DC 10 Wisdom saving throw.

Ritual Magic

Any spell may be cast as a ritual. Spells that have the ritual tag may be cast as a ritual as per the existing rules. Otherwise, the following rules apply.

To cast a spell as a ritual, you must:

  • Spend viz or arcane reagents in GP* value equal to 10 x spell level2
  • Reference a ritual (or spell) book that has the spell
  • Have the ritual casting feat or class feature

Where We Last Left Off

At the beginning of the session, one player should give a brief retelling of the previous session. That player’s character gains inspiration. Any player that wrote up a session report for the previous session gains inspiration.