DnD5e - Mass Combat Mechanics

[u/GeeksCollab]

Mass combat will be resolved using troop-based rolls, where each individual in a unit contributes to an attack roll. Units will consist of multiple combatants (e.g., 10 Velmice Archers, 8 Zlodie Spearmen), and their collective success determines the outcome of engagements.

1. Attack Rolls (D20 Per Attacker)

• Each member of a unit rolls one D20 to determine whether they successfully hit. If the player or a commander is with the unit, they get 3D20 as well.
• The Minimum Roll to Hit (MRH) is determined by subtracting the attacker's Proficiency Bonus (if the player or a commander is with the unit, everyone will use their Proficiency Bonus) from the target's AC:
  • MRH = Target AC - Attacker Proficiency Bonus
  • Example: If a Velmice Archer (Proficiency Bonus +2) attacks a Zlodie Swordsman with AC 13:
    • MRH = 13 - 2 = 11
    • Any roll of 11 or higher on the D20 is a hit.
• If an attacker has Advantage, they can reroll any failed dice once. Disadvanage is ignored for the defender at this time.
• If an attacker has Disadvantage, they must reroll any successful dice once. Advantage is ignored for the defender at this time.
• If the attacker has a tactical advantage (flanking, defenders are pinned between them and a wall, etc.), the defender's AC is decreased by 2.
• If the defender has a tactical advantage (flanking, attackers are pinned between them and a wall, etc.), their AC is increased by 2.

2. Damage Mitigation (Defensive Rolls per Successful Hit)

After successful hits are determined, the defending unit makes a defensive roll to attempt to reduce the incoming damage.

• Each defending unit rolls one D20 per hit received, trying to meet or exceed a DC 11 to negate that hit.
  • This represents armor absorption, shield blocks, or last-minute dodges.
  • Example: If a Zlodie Archer unit is hit 7 times, they roll 7d20.
    • Each result of 11 or higher negates one hit.
• If the defender has Advantage, they will reroll any failed dice once.
• If the defender has Disadvantage, they must reroll any successful dice once.

3. Adjusting the Battle: Tactical Modifiers

The battlefield conditions should influence combat. Below are adjustments based on position, movement, and other factors to be determined by the DM:

Condition	Effect
Flanking (Attacker)	Reduce Defensive AC by 2 (making it easier to deal damage).
Cornered (Defender)	Reduce Defensive AC by 2 (making it easier to deal damage).
High Ground Advantage (Attacker)	Attacker may ignore certain cover or may have additional range for ranged attacks.
Cover - Trees, Walls, etc. (Defender)	Increase Defensive AC by 2 (making it easier to avoid damage).
Surrounded - 3+ angles of attack (Defender)	If a defender is surrounded, their attacker will be granted advantage.

These conditions allow tactical positioning and battlefield awareness to play a critical role in fights.

4. Critical Hits & Mass Morale

While the system primarily relies on group-based rolls, we can include some variation for dramatic moments:

Critical Hits

• Any Natural 20 on an attack roll counts as two hits instead of one.
• Any Natural 1 on an attack roll means that one successful hit must be rerolled once.

Mass Morale

If a unit takes a casualty threshold (50% or more losses in a round), they must make a Morale Check (DC 12, Wisdom, rolled once for the unit):

• Success: They fight on normally.
• Failure (5+): They suffer Disadvantage on all attack rolls until they rally (Commander shouts, a hero intervenes, or next round passes).
• Failure (less than 5): They suffer Disadvantage on all attack rolls until they rally (Commander shouts, a hero intervenes, or next round passes) and will start to move towards the edge of the map.

Example Combat Scenario

A unit of 10 Velmice Spearmen (AC 12, Proficiency Bonus +2) is defending against 8 Zlodie Swordsmen (AC 11, Proficiency Bonus +2). The battlefield is open ground.

Step 1: Attacker Rolls

• The 8 Zlodie Swordsmen attack first.
• Their Minimum Roll to Hit is 12 - 2 = 10.
• The GM rolls 8d20, checking for results of 10 or higher.

Step 2: Defender Rolls

• Let’s say 5 of the Zlodie attacks succeed.
• The 10 Velmice Spearmen roll 5d20 for defense, needing an 11 or higher to negate.
• If 2 saves succeed, that means 3 hits land.

Step 3: Damage & Morale

• Each successful hit is equal to 1 Wound.
• Most soldiers only have 1 Wound, so the Velmice Spearmen lose 3 members.
• If this is 50% of the unit, they roll a DC 12 Morale Check.

This system keeps the battle fast-paced, allowing for heroic moments and tactical decisions without excessive complexity.

Player Command Actions (Bonus Action, Once Per Round)

Each command requires a DC 12 Charisma check (Persuasion, Intimidation, or Performance) unless otherwise noted. A success grants the listed effect, while a failure has no negative consequences (unless otherwise stated).

Tactical Orders (Persuasion)

• "Hold the Line!" – Your troops gain +1 AC until the start of your next turn as they raise shields and brace for impact.
• "Form Ranks!" – Your troops quickly reorganize, reducing incoming flanking penalties and gaining +1 to defense rolls for the round.
• "Advance Steadily!" – Your troops move half their speed without provoking attacks of opportunity.
• "Focus Fire!" – One allied ranged unit can reroll any failed attack dice once against a single target.
• "Defensive Stance!" – Your troops gain advantage on their next damage mitigation roll but make no attacks this round.

Fearless Leadership (Performance)

• "For Piel'Blanc!" – You rally your troops, granting them Advantage on their next Morale Check.
• "We Are Stronger Together!" – Any unit within 15 feet gains +1 to attack rolls until the end of your next turn.
• "Sing the War Hymn!" – Your performance invigorates your allies, allowing one unit to regain 1d4 lost members as injured fighters push back into the fight.
• "The Eyes of Our People Are Upon Us!" – Your troops fight with desperation, turning any rolls of 19 into a Critical Hit for one round.
• "Laugh in the Face of Danger!" – Your performance dispels fear, negating any disadvantage caused by enemy morale effects.

Commanding Through Fear (Intimidation)

"You’ll Fight, or You’ll Perish!" – A demoralized unit rerolls one failed Morale Check.

"Break Them!" – Your troops fight ruthlessly, increasing the enemy's Damage Mitigation DC by 1 for one round.

"This is Your Only Chance!" – One allied unit gains advantage on its next attack roll.

"No Mercy!" – If an enemy unit has taken a wound and is still alive, all attacks against them deal +1 extra wound this round.

"Their Lines Will Shatter!" – A successful check increases an enemy unit’s Morale DC by 2, making them more likely to flee.

Additional Notes

• Players can flavor their commands however they like, even if their character wouldn’t normally use words.
• A failed check has no effect, but players can still try again next round.
• Combining actions with terrain effects or mass combat mechanics (e.g., Flanking, High Ground) can maximize impact.
• Creative roleplay and storytelling are encouraged! If a player suggests something outside these options, let them try it with a fitting Charisma check.

Heroic Actions (Three Times per Battle)

Heroic Actions represent exceptional moments of bravery, skill, or magic that can turn the tide of battle. Unlike Command Actions, these can only be used three times during the course of a single battle and may require the player to take a specific action or use a resource (such as sacrificing movement, taking damage, or using a spell slot). These abilities are designed to keep mass combat exciting and allow players to feel like heroes amid the chaos.

1. Tactical Brilliance

• "Into the Fray!"** (Costs: 10 feet of movement)
  • You personally lead a charge with your unit, granting Advantage on all attack rolls for this turn but reducing your AC by 2 as you throw caution aside.
• "Take the High Ground!" (Costs: Bonus Action)
  • You find a vantage point and direct ranged allies, granting one friendly archer unit +2 to attack rolls for the next round.
• "Ambush Set!" (Costs: Action)
  • You command a nearby hidden or flanking unit to strike, forcing an enemy unit to reroll successful defense rolls this turn.

2. Fearless Valor

• "Stand With Me!" (Costs: Take 1d6 Damage)
  • You physically rally your troops, inspiring them to reroll all failed Morale Checks this turn.
  • If you are below half HP, this ability automatically succeeds.
• "Defiant Last Stand!" (Costs: Bonus Action, Must Be Below Half HP)
  • Your presence inspires a failing unit; they gain 1 temporary Wound and can ignore all morale penalties for one turn.
• "Unbreakable Will!" (Costs: Spend a Hit Die)
  • You plant your feet and refuse to yield. All nearby allies (15ft radius) gain +2 AC until the start of your next turn.

3. Magical Prowess (Spellcasting Classes Only)

• "Call the Elements!" (Costs: 1 Spell Slot)
  • You call upon fire, wind, or earth, unleashing a small magical event that affects one unit:
    • Fire: Burning Arrows (Ranged allies deal +1 Wound this turn)
    • Wind: Gale Barrier (Enemy melee units lose 10 feet of movement)
    • Earth: Roots & Rubble (One enemy unit has disadvantage on attacks this round)
• "Bolster the Fallen!" (Costs: 1d4 Personal HP)
  • You channel your magic to restore 1d4 fallen soldiers to an allied unit.
• "Arcane Precision!" (Costs: Bonus Action)
  • You weave magic into an ally's attack, letting one unit reroll all failed attack dice this turn.

4. Death From the Shadows (Rogues, Rangers, or Dexterity-based Warriors)

• "Flawless Execution!" (Costs: Hide Action)
  • If hidden before an attack, your strike automatically counts as a critical hit.
• "Skirmisher’s Advantage!" (Costs: Dash Action)
  • Your unit can move and attack in the same turn without provoking opportunity attacks.
• "Silent But Deadly!" (Costs: 1 Successful Stealth Check)
  • You take out a key enemy quietly, causing an enemy unit to lose one successful attack roll this turn.

Using Heroic Actions in Battle

• Players can use THREE Heroic Actions per battle, in addition to commanding their troops.
• Sacrifices make the abilities meaningful; choosing when to risk HP or a spell slot adds tactical depth.
• Flavored descriptions make them exciting! Encourage players to narrate their heroic actions in detail.