Dungeons & Dragons: How To Update First Edition Monsters to 5e

Out with the new, in with the old.

Dungeons & Dragons has been around for half a century, and in that time several editions have been released with updated rules and mechanics. Often this is for the best, but not everything from older editions gets updated for the next edition immediately, and some monsters, mechanics, races, and classes are never imported before the next edition comes out. So what can you do as a DM when you stumble across a cool monster First Edition that you want to use in your Fifth Edition campaign?

You can't just pull a monster directly into newer editions because the way stats and mechanics work changes over time. For example, 18 Armor Class (AC) was only decent in 3rd edition but can feel impenetrable in 5th. That's why you need to both import and scale your monsters. So listen up, Dungeon Master, and we'll guide you on how to modernize your favorite monsters!

Why Update Monsters?

The Monster Manual gives you plenty of monsters to work with for a basic campaign, and additional supplements have additional monsters. But they aren't exhaustive. What if your story hinges on the party encountering a steel dragon, but there are no contemporary stat blocks? What if you find an obscure monster in an old Dungeon magazine at a flea market, one that your players would love, but it's never been used outside that forty-year-old magazine?

You could always homebrew a monster with a similar theme, but it's reasonably simple to convert an existing stat block. That way you won't need to worry about accidentally making your monster far too weak or strong for your party to handle. Fortunately, first and second edition monsters are relatively simple to update as long as you aren't trying to do a full conversion.

Updating Your Monster

Armor Class

To convert your vintage monster's armor class, take the provided AC and subtract it from 19. If you happen to find a monster with negative AC to convert, follow the same formula, but don't allow the converted AC to exceed 22.

5th Edition AC = 19 — 1st Edition AC

Hit Points

In First Edition, eight-sided dice were used for monster hit points, and all monster entries include Hit Dice (HD), the number of d8s to roll to determine their HP. This makes calculating HP simple: Just take the listed HD and multiply by 4.5.

5th Edition HP = HD × 4.5

Speed

To calculate movement speed, multiply the given speed by five. Do this for each speed category, except for web speed. If a monster has a web speed, give it the Web Walker ability found on creatures such as the Giant Spider.

5th Edition Speed = Speed × 5

Attack Roll Modifiers

Rather than using both ability and proficiency modifiers, calculate a flat attack roll modifier using the HD. Divide HD by two, and add two for a maximum of +12.

5th Edition Attack Modifier = 2 + HD/2

Saving Throw DCs

Monsters with attacks, spells, or abilities that require a save should have their save DC calculated based on hit dice. Simply divide HD by two and add eight.

5th Edition DC = 8 + HD/2

Saving Throws

Monster saves can be classified as good, bad, and neutral. Use your best judgment as to what kind of saves a monster should be good at, and for those rolls, apply a modifier of half the hit dice plus two (2 + HD/2). For neutral saves, use no modifier, and for saves that the monster should struggle with, use a negative modifier up to -4.

Stats

Stats are the trickiest thing to update, because none of the contemporary stats were used in the earliest editions except intelligence, which is only described as a range, not numerically. For intelligence, use the following conversion table:

For other stats, try to find the most similar monster in 5th edition and use that creature's stats, adjusting as necessary.

Spells And Abilities

If the legacy monster has any spells or abilities, the easiest way to update them is to look for the nearest analogs on a contemporary monster or sourcebook and copy them directly. If a devil can throw a fireball, give it the Fireball spell as an ability. If it attacks with claws, copy the Rake attack from a lion or tiger in the Monster Manual.

Many monsters have additional abilities described in their text box rather than in a stat box. Be sure to read through the full text to pick out all relevant abilities!

Groups And Treasure

1st Edition monsters tended to come in larger groups and carry more treasure than in later editions. As a rule, decrease the number of monsters in a group if it exceeds five in 1st Edition, and normalize treasure to your current adventure.

Sample Monster

To demonstrate how effective this method is, let's apply it to a classic monster from the 1979 Advanced Dungeons & Dragons Monster Manual and then compare the results to the same monster in the 5th Edition Monster Manual. For this demonstration, we'll use everyone's favorite miniature dragons: kobolds.

Here's the kobold stat block from the AD&D Monster Manual:

While this gives you some good information, it isn't terribly useful in the 5th Edition system. In fact, a lot of it isn't used in 5th edition, and can be ignored. Converting as described above, and using the stat block of goblins as the similar humanoid monster for stats, gives the following result:

This gives you a much more useful stat block, which can be immediately used for your 5th edition campaign. These kobolds are weak enough to take out with a single hit, just like you'd expect from an early-game threat.

Compare this to the stat block from the 5th Edition Monster Manual:

The converted kobold was only off by one point in four stats and one HP when compared to the official version, and had two more languages. The only other changes were the addition of Pack Tactics in 5th Edition and a change of weapons, with kobolds trading their clubs and short swords for daggers and slings.

The addition of Pack Tactics should remind you that monsters tended to come in much larger groups in older editions. Kobolds were listed as grouping from 40-400 individuals, which would be a nightmare to run as a DM. This new ability allows you to significantly reduce the group while maintaining the threat of a kobold war party.