“Seize the intruders!” The king gestures at the party, and a dozen guards march forward, spears leveled. In response, the fighter darts forward through a thicket of spears and swings her blade. The blow connects—a guard drops! But the fighter has put herself in a dangerous position, right on the guards’ front line. Before she can recover, three guards lunge at her with their spears. Can she survive this deadly triple attack?

A deadly combat against a dozen fearsome foes can be quick, tense, and exciting, especially at low levels when characters and opponents alike have relatively few hit points. At medium and high levels, though, the nature of combat changes. For 10th-level characters, for instance, a level-appropriate battle against twelve CR 2 guards can be fairly slow: with each guard having around 50 hit points, and possibly a multiattack action as well, it’ll be a while before the party hacks their way through the guards and faces off against the evil king. On the other hand, if the same party faces a retinue formed of low-CR monsters, the battle will be quick but not particularly tense, with most of the guards’ attacks missing or dealing trivial damage.

A horde monster is a new type of Level Up opponent that facilitates quick, exciting battles against large numbers of opponents, no matter the level of your characters. Like elite monsters, they allow the Narrator to control the scope and complexity of a combat encounter.

Monstrous Menagerie II: Hordes & Heroes contains dozens of horde monster stat blocks, as well as the horde monster template.

The Horde Monster Template

You can turn nearly any existing monster into a horde monster, as long as its CR is 1 through 20.

The Horde Monster template changes the monster’s hit points, actions, and damage.

Hit Points: A horde monster’s hit point maximum is 8 + Challenge Rating + Constitution modifier.

Actions and Damage: Each round, a horde monster can move and take a single action; it can’t use bonus actions, legendary actions, or damaging traits. Its actions are typically simple and can deal damage only once per round: it doesn’t make several attacks via Multiattack actions or effects that can normally target multiple creatures. When it deals damage, it gains a bonus to its damage roll equal to its Challenge Rating. It doesn’t roll extra weapon dice because it’s larger than Medium.

If a horde monster’s attack would typically force a saving throw or trigger other special effects, the special effect only occurs on a critical hit. 

XP and Encounter Building

A horde monster of Challenge Rating 1 through 4 grants 40 percent the normal XP for a monster of its CR. For encounter building, five CR 1–4 horde monsters can be used to replace two standard monsters of the same CR.

A horde monster of Challenge Rating 5 through 20 grants 20 percent the normal XP for a monster of its CR. For encounter building, five CR 5–20 horde monsters can be used to replace one standard monster of the same CR.

Kobold Dragon Warrior Challenge 15

Horde Small humanoid   2,600 XP

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AC 15

HP 25 (bloodied 12)

Speed 30 ft.

Initiative Dex +5 (15), Insight +2 (12), Perception +2 (12)

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STR DEX CON INT WIS CHA

10 (+0) 20 (+5) 14 (+2) 10 (+0) 14 (+2) 10 (+0)

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Proficiency +5; Maneuver DC 18

Saving Throws Str +0, Dex +5, Con +2, Int +0, Wis +2, Cha +0

Senses darkvision 60 ft., passive Perception 12

Languages Draconic

Pack Tactics. The kobold has advantage on attack rolls against a creature if at least one of the kobold’s allies is within 5 feet of the creature and not incapacitated.

Sunlight Sensitivity. While in sunlight, the kobold has disadvantage on attack rolls, as well as on Perception checks that rely on sight.

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ACTIONS

Scimitar. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 23 (1d6 + 20) slashing damage.

Sling. Ranged Weapon Attack: +10 to hit, range 30/120 ft., one target. Hit: 22 (1d4 + 20) bludgeoning damage.

Horde Monsters vs Standard Monsters and Elite Monsters

A horde monster represents one of a big group of tough but unexceptional monsters (rank and file soldiers, beast pack members). It's weaker than a character with a level matching its CR. It's usually found in large groups, often led by an elite monster or one or more standard monsters.

A standard monster represents an opponent strong enough to lead or operate on its own (a solo hunter, part of an elite team, or an officer commanding a horde). It's generally stronger than a character with a level matching its CR. It's usually found leading a horde or in a small group.

An elite monster represents an apex predator (a warlord or a fearsome lone monster). It's a challenge for an adventuring party with a level matching its CR. It's usually found alone or leading a horde.

When to Use Hordes

Horde monsters have attack bonuses and defenses appropriate to their Challenge Rating, so they can stand toe to toe against adventurers whose levels are around their CR (and even hang in against characters with levels up to twice their CR). The horde template isn’t intended for Challenge Ratings under 1 (low-CR monsters are already designed like horde monsters and can be used in much the same way!) or above the party level (each high-CR monster should be significant and challenging). 

Area effects are efficient horde-slayers. A single fireball could wipe out half of a group of CR 5 horde creatures. This means that a horde-heavy battle gives wizards and other area attackers a chance to shine. This is good! Let the adventurers blow up the occasional attacking army. But to make things a bit of a challenge, split up your horde into groups or have them enter the battle in waves. 

How often should you use hordes in combat scenes? As with all combat decisions, you can let the story lead you. Any time the scene calls for the adventurers to be outnumbered, hordes offer a useful tool. If your players enjoy the challenge of standing against waves of attackers or of fighting tactical battles against a boss and their lackeys, then hordes can become an important encounter-building tool.