How to Convert 4e Monsters to 13th Age by ASH LAW

ASH LAW designed some of our favorite monsters in the 13th Age Bestiary (which you can buy here.) Her latest project is the Midgard Bestiary for Kobold Press, converting 100 monsters designed for D&D 4th edition to 13th Age.

We asked ASH to share her process for converting 4e monsters to 13th Age, and we’ve included some sample monsters at the end.  

Also: from now through April 1, you can take $5 off the Midgard Bestiary, 13th Age Compatible Edition at the Kobold Store with the promo code P3LGR4N3. (You can actually use it for any Kobold Press product with a minimum $5 purchase.)

How to convert a 4e monster to 13th Age in 13 steps

I did most of the mechanical conversion for Kobold Press’ Midgard Bestiary: 13th Age Compatible Edition by hand, in red pen and highlighter, in a car, during a daily commute and lunch breaks. (Though not while driving!) The 13th Age core book was on one knee, non-13th Age material on my left knee.

  1. Highlight anything that 13th Age does not have: Prone, push, that sort of thing. If it was integral to something that is thematically central for the monster I found a way to deal with it. If it was just an extra effect then I’d cross it out and ignore it. I generally didn’t cross it out straight away, because sometimes it wasn’t immediately obvious and I wanted to section it off with highlighter.
  2. Group similar attacks together. If something has a ‘basic axe attack’, a ‘mighty axe charge’, and a ‘great axe sweep’ – yeah, cross all those out and make a note “Axe”.
    1. If great axe sweep and so forth are actually different things that the axe does (instead of just a slightly better axe attack) I’ll make them conditional riders for the axe attack.
    2. Give the axe attack a decent name:
      Mighty Axe +X vs AC –  Y damage
      Natural even hit: Z damage or effect
  3. Determine the creature’s level. Generally that is (4e level/2)-1and round up or down to taste. So a 15th level 4e monster might be a (15/2)-1 = 6.5 level monster… so 6th or 7th. I then might bump up or down a level depending on if it feels right depending on its 4e ‘fiction’ (its place in the world).
  4. Fill in numbers for attack bonuses based on level. If something is thematically supposed to be good at something (an archer monster making ranged attacks) I’ll give attacks that fit the theme +1 and those that don’t fit a -1.
  5. Write in the total damage an attack is supposed to do beside the attack. If the attack has a conditional rider I’ll divide the damage between the two, and either frontload it slightly or bump up the damage on the rider part. So if a creature is supposed to do 12 damage (say a 6th level mook) and it has a conditional rider that happens half the time it might look like this:Mighty Axe +11 vs AC – 10 damage
    Natural even hit: 4 damageor like this:Mighty Axe +11 vs AC – 4 damage
    Natural even hit: 10 damageThe idea is that over the course of 2 hits it should average out as the ‘correct’ 12 damage.The first example is fine. On average it does 12 damage. The second example on average does 9 damage, but feels more impressive when it hits… so to balance that out I’d give it a little (+1) boost to its to-hit.Mighty Axe +12 vs AC – 4 damage
    Natural even hit: 10 damageThere! Now that mook does damage as though it was one level lower, but is hitting like it is one level higher (and its hits feel really impressive half the time). Generally I’d go with the first example unless the monster’s fiction had it be weak but with a powerful secondary attack.

    Goblin Scorpionataur’s Axe +12 vs AC – 4 damage
    Natural even hit: 10 poison damage from the striking tail of the half-scorpion goblin.

  6. Pop the defenses and HP in.
  7. Loop back for any powers or attacks with multiple targets, and adjust so that the monster’s damage output over several rounds roughly matches what the strike damage should be. In general if something is attacking 1d3 targets it should only do 1/3rd damage to each target. I actually aim for something closer to 2/5ths to each target.
  8. Loop back for anything still in highlighter (prones, pushes, etc). If they are relevant to the monster I’ll add them in as a special power triggered by an attack or something. Pushes and prones can generally become pops-free-then-must-save-or-X, but mostly they can be dumped when converting to 13th Age without losing the theme and feel of a creature.
  9. Shake my head. Tut loudly. Stare at traffic.
  10. I’ve made a mistake, this monster should be one level higher because…
    a) It feels like it should be tougher.
    b) It feels like it should hit more often.
    c) I’ve just converted an X and there is no way a Y mook is weaker than an X but I can’t bump the X down because it needs to be stronger than the Z.
    d) I’ve changed my mind.
  11.  Use Jonathan’s advice on how to bump monsters up in power (+X to hit, or +X% HP, or +X to defences). Adjust the monster until it feels right, and the numbers are not incomparable to other similar creatures in the core book.
  12. Use the level of the original 4e monster as its initiative modifier, but adjust for feel based on what kind of monster it is.
  13. Have a cup of tea.

Beyond the mechanics

Exploring the monsters in both Bestiaries by giving them things to have, adventure hooks, and treasure was a bunch of fun. It was challenging in a different way – after the 20th stat-block conversion you kind of get into the swing of it, but every monster presents fresh narrative challenges when giving hooks and things in its pockets.

Designing from scratch

If I had been approaching the Midgard Bestiary monsters fresh rather than doing a conversion of existing material, some of them would have been very different mechanically, because the underlying fiction would have been different. Mechanics flow from the fiction, and sometimes feed back into it too. For an example of how to start from a blank slate look at the chapter I wrote at the end of the 13th Age Bestiary on how to create monsters which goes step-by-step through the design choices in creating a ‘Lyznakian Fire Wizard’.

13th Age Bestiary Preview: Orcs

Download ASH LAW’s take on orcs for the 13th Age Bestiary in a glorious laid-out PDF.

Midgard Bestiary Preview: Goblins of the Wasted West

(Shared here with the kind permission of Kobold Press and its Kobold-in-Chief Wolfgang Baur.)

Midgard Ghost Goblin by Chris McFannThe Old Ones did it. They changed the buggers. It wasn’t the heat, or lack of food, or just not being civilized. These goblins live in the shadow of another world and can’t be compared to anything natural in all of Midgard. No one creature better represents the corruption and variety of the dangers in the Wasted West than the goblin. Nowhere else in Midgard will you find a race so different from tribe to tribe.

The goblins below are but a small selection of the unique goblin cultures found throughout this unforgiving land…

Ghost Goblin Tribe

The Ghost Goblins have strong ties to their dead in more than just a spiritual sense. When their warriors die, tribal necromancers create unliving soldiers to fill the ranks. So devoted are they to this practice that the undead obey all members of the tribe instinctively, even from those with no talent for spells.

Some warriors among the Ghost Goblins hold the undead in higher esteem than the living. They strive to honor the zombies through their actions, and through prayers to strange gods. Soon a ghost goblin horror is born, too intelligent to be considered a zombie but too unnatural to be called a living creature.

As its flesh slowly begins to rot away, a horror begins to develop a talent for tugging at the souls of others. The horror exists halfway between life and death, suffering vulnerabilities of both the living and unliving. This place between worlds grants it power, however. The ghost goblin horror can implant the suggestion of death in an enemy’s mind, paralyzing its body with the rigor of the dead before attacking relentlessly. The ghost goblin horror does not fear death and will retreat from battle only if ordered by a necromancer or priest.

Dust Digger Tribe

The Dust Diggers scour the waste in search of long abandoned artifacts. These strange goblins seem supernaturally talented in getting vril technology working again. Most members have an odd vril trinket in their arsenal. Some of them have even modified their bodies, seeming more construct than flesh.

The dust digger watchmen are charged with protecting the excavations of the tribe. They take up a positions that grants cover and makes them difficult to see, whenever possible, but do not sacrifice proximity to the excavation site. When enemies come too near, the watchman opens fire and shouts for reinforcements.  Watchmen typically fight alongside other warriors, they support mobile skirmishers well. Dust Diggers are also found with strange constructs and war machines excavated from vril ruins.

Bonewraith Tribe

The cannibalistic bonewraith tribe are speakers with spirits, and some say with the Old Ones themselves. Ceremonial leaders among the bonewraith tribe, the spirit callers are masters of ritual and can commune with large numbers of spirits. Their bone weapons and tools are carved with beautiful—if disturbing—images, and their hide armor bears the grisly, weathered faces of former enemies.

Spirit callers generally partake of goblin flesh more than other tribesmen. They can be recognized by their twitching hands and over-dilated pupils. In combat they can connect to an enemy’s soul and then use this connection to force their target’s limbs to move against the victim’s will.

The Bonewraith tribe generally doesn’t work with non-goblins, but they may make temporary alliances and do on occasion tame beasts as mounts or combatants.

Things You Might Find On A Ghost Goblin Horror…

Tiny bone disks carved with goblin prayers. Metal helm, exhortations to strange gods scratched into it. Maggots fat from the flesh of the decaying goblin. Mismatched pieces of armor, scavenged or taken from the bodies of slain enemies.

Things You Might Find On A Dust Digger Tribe Goblin…

Large bone knife. Chest containing broken artifacts. Goggles. Pliers. Tarnished coins with holes drilled into them, and star-charts scratched into their faces. Map of the wastes. Warm rock which glows slightly in the dark. Tea pot. Necklace of steel teeth. Dowsing rod. String of sand-glass beads. Jar containing a twisting bit of frozen time—if unfrozen over a fire it reveals the last words of a dying wizard. A chest containing 49 smaller chests, one inside the other, until the final chest which contains a tiny cloth doll.

Things You Might Find On A Bonewraith Goblin…

Armor made from the faces of victims. Bone sword, made out of the bones of victims. Pouch, made out of the skin of victims. Trousers, made out of the flesh of victims. Vile totem made out of soulstuff and bones.

Magic Items

Vril Power Bow (bow). A priceless artifact from a lost time, but sadly not as reliable as it was when it was new. At the start of each of your turns, roll a d8. If you roll over the escalation die value, on a successful hit with this weapon add the die result to your damage and the target briefly glows. If you roll under the escalation die, you take the die result in damage and you briefly glow. Rolling equal to the escalation die applies no damage from the roll, but you can make another attack with the bow on this turn as a quick action.

Quirk: Dream of lost ages, seek to restore that which was lost.


Goblin Totem (holy or unholy symbol). The artifact is unmistakably goblin in design, but started life as a holy symbol for a different god. Gain +1 to hit for every goblin ally in the battle, including yourself if you are a goblin, to a maximum of +6.

Recharge 16+ (Ghost Goblin tribal totem): On a successful hit with a single-target melee attack, the target is seized with rigor mortis (stuck, save ends).

Recharge 16+ (Bonewraith tribal totem): On a successful hit with a single-target melee attack against a foe with half your total hit points or fewer, the target is terrified by a vision of goblin ancestral spirits (fear, save ends).

Recharge 16+ (Dust Digger tribal totem): On a successful hit with a single-target ranged attack, the target is dazed by powerful vril energy (save ends).

Quirk: Sing traditional goblin songs such as “Three Dirty Goblins”, “The Goblin’s Eyes” and “Goblin’s Lament”. If you sing the songs for long enough they may drift into unholy hymns to the Old Ones without you noticing.

Adventure Hooks

The Goblin Market: A shiver of goblin sharks have come to town, far from their home, to meet and trade with representatives of the bonewraith tribe. The situation is potentially explosive—especially as the items the bonewraiths are trading belong to the ghost goblins, and the shark goblin’s items were stolen from dust diggers.

Ghost Goblin Horror

The ghost goblin horror fights alongside other living and undead tribe members. Sometimes the tribe will take in undead discovered in travels and raids. These creatures were often not goblins in life, so there is no end to the variety of undead they might command.

Level 2 troop [Undead]

Initiative: +5

Vulnerable: holy

Short sword +6 vs. AC—5 damage

Natural even hit or miss: The goblin may use curse of rigor as a quick action.

R: Curse of rigor +6 vs. MD—5 damage and the target is stuck (save ends).

Ghost life: When the ghost goblin horror is reduced to 0 hit points it makes a save. If it succeeds it gains 5 hit points and regenerates 5 hit points per turn until the end of the battle or it is next reduced to 0 hit points.

Fear aura: Enemies engaged with the goblin and who have 12 hit points or less are dazed and can’t use the escalation die.

AC 17

PD 11          HP 27

MD 15

Dust Digger Watchman

Dust digger watchmen guard major excavation sites against looters. Surprisingly disciplined, these goblins know the power of the artifacts they seek. They have mastered the strange vril bows whose bolts are charged with the power of the sun. When they open fire, reinforcements are never far behind.

Level 2 archer [Humanoid]

Initiative: +8

War pick +7 vs. AC—7 damage

R: Vril powerbow +7 vs. AC—7 holy damage

            Natural 16+ hit: Target glows and is vulnerable to all attacks until the end of its next turn.

AC 18

PD 16        HP 36

MD 12

Bonewraith Spirit Caller

The Bonewraith goblins are known for eating both their enemies and the weak and fallen of their own tribe. They fashion the resulting bones into weapons, totems, and armor, to imbue themselves with the power of the fallen. Most who encounter these fearsome creatures flee rather than find out the truth of these claims.

Level 2 caster [Humanoid]

Initiative: +6

Bone sword +7 vs. AC—7 damage

R: Soul grasp +7 vs. MD—7 damage and the target pops free

R: Summon ancestors +7 vs. PD—7 damage

            Natural 18+ hit or miss: Causes fear in 1d3 nearby enemies (save ends).

[Triggered action] Spirit guardian: When the spirit caller becomes staggered it gains +2 to all its defenses until it is next hit.

AC 18

PD 16       HP 36

MD 12

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