You can use the monsters included in the 13th Age Archmage Engine, or you can make your own.

Monster Rules

Stats & Characteristics

Most monster attacks generally deal a specific amount of damage (instead of rolling for damage) and don’t add on the escalation die. Only exceptional monsters get to add the escalation die to their attacks.

Monsters may have particular abilities or powers that are triggered when the attack roll is greater than a certain threshold. The default trigger happens at a 16+ monster d20 attack roll, though unpredictable monsters may have effects trigger on other rolls.

Mooks

Mooks are weaker monsters that can be cut down in large numbers in a single turn. Damage is not tracked against single mooks, but against the entire mob of mooks you’re facing. If you roll damage against a mook and it is greater than the single mook’s hit points, then another mook takes the remainder. In this way, damage can cascade to multiple mooks, and a player can kill multiple in one turn, even if they’re not all directly within your attack range.

A mook’s hit point value is one-fifth that of a regular monster.

Mooks move and attack individually. Mooks deal a fixed damage when they hit, and double damage when they roll a natural 20.

Mooks can be split up into multiple mobs with different initiative numbers and hit point pools for each.

Large & Huge Monsters

Large monsters generally have twice the hit points and deal roughly double the damage of a normal-sized monster. They also count as two monsters when you build a battle.

Huge monsters have triple the hit points, deal triple damage, and count as three normal-sized monsters when you’re putting together a battle.

Regular-sized monsters may also have the same stats as large and huge monsters, in which case they are labeled as double-strength and triple-strength monsters, respectively.

Abilities

Monsters may have special abilities for use in battle.

Burrowing

Burrowing is a special rule for monsters that allows somewhat restricted movement underground. Unless otherwise specified, monsters generally do not leave functional tunnels behind them when burrowing.

A burrowing creature on the surface may attempt to burrow underground by using a standard action. Burrowing is successful if a saving throw beats the required save for the type of ground.

After successfully burrowing, a creature may move underground, faster or slower depending on the hardness of the ground, out of sight of other creatures, hidden and safe from attacks.

For breaking through to the surface, the sequence is as follows: a move action from deeper under the ground to come close to the surface, close enough that people see there’s something coming, followed by a quick action to break through, and then by a standard action attack.

Death Attacks and Last-Gasp Saves

Some deadly monsters have a special attack called a death attack that can kill (petrify, paralyze, liquefy, immolate) in a single attack. Such attacks offer the player a last-gasp save.

A player that is affected by a death attack has a limited amount of last-gasp saves to try to throw off the condition of the death attack. On the first turn a player is affected, the player may make a single action (standard, move, or quick), after which they must roll a hard save (16+). If successful, the player shrugs off the death attack condition and can act normally on their next turn. If unsuccessful, their turn ends and the player may not take any other actions on future turns except for further last-gasp saves. Each successive last-gasp save is a hard save (16+). A successful save means that the player can act normally on the next round, unless the player rolls a natural 20 for their last-gasp save, which means that the player can take their turn normally in the current round.

Once a player fails four last-gasp saves while fighting off the death attack, the death attack effect succeeds, and the player is adversely affected as the attack indicates.

An ally may assist a player affected by a death attack. The ally must use a standard action to help the player shake off the attack. This gives the player a free last-gasp save that may be rolled immediately. (A failure doesn’t count against the four allowed saves.) In addition, the assisted save becomes normal difficulty (11+) instead of hard.

Fear

Some monsters may have an aura of fear that makes them more difficult to be attacked.

A character engaged with such a monster must have a certain amount of hit points (according to the level of the monster with the fear aura) or be dazed (-4 attack) and gain no benefit from the escalation die.

Should the character’s hp increase past the fear threshold or the character disengage from the monster, they lose the dazed effect and regain the escalation die benefits.

Group Abilities

A few monsters have limited abilities that can be used a certain number of times in a battle for the group. Any monster within that group may use the ability, but then the number of available uses is decremented for the entire group. It does not matter which monster uses the ability.

Mooks cannot have group abilities.