Three Ways to Face the Mythos: Chaosium, Edge Studio and Modiphius Compared
H.P. Lovecraft’s Mythos is built on one idea: humanity is small, the universe is indifferent, and knowledge is dangerous. Putting that into a game raises a design question. How do you make players feel dread while still giving them something to do? Three publishers answer it in three different ways.
A quick note on the lore
Whichever game you pick, the shared material is the same. There are ancient entities such as Cthulhu, Yog-Sothoth and Nyarlathotep, forbidden books, secretive cults, and investigators who learn too much. The games differ in how much of that is a threat you can fight and how much is a truth you can only survive.
Chaosium: Call of Cthulhu
Chaosium’s game is the benchmark, and the others are judged against it. It runs on percentile dice, with skills as percentages and success meaning you roll under them. Sanity is its signature mechanic, and it keeps ticking down as you meet the unnatural.
- Complexity: Moderate. The core maths is simple, but the rulebook is large, and a good Keeper has to manage investigation structure, clue flow and pacing.
- Tension: The highest of the three. Investigators are fragile, combat is a last resort, and the real danger is losing your mind rather than your hit points. Failure is part of the story.
Edge Studio: Arkham Horror RPG
This is the newcomer. Edge Studio is the RPG arm of Asmodee, built largely from the Fantasy Flight Games roleplaying team, and it is the first time Edge has made an original RPG system. That system is the Dynamic Pool System. It uses standard six-sided dice, and sometimes you can simply spend a die from your pool to succeed rather than roll. Instead of Sanity points, it uses horror dice.
- Complexity: The lowest of the three on paper. The starter set requires no prior knowledge of tabletop RPGs, board games or Arkham Horror, and it comes with physical components such as maps, tokens and handouts. Spending dice from a pool does add some tactical choices.
- Tension: Medium. One reviewer found the investigators more capable and combat-ready than their Call of Cthulhu counterparts, which suits the pulp feel but may put off some players. Another reviewer describes it as a pulpier Call of Cthulhu, aimed at making Mythos roleplaying more accessible.
Modiphius: Achtung! Cthulhu
Modiphius takes the biggest step away from classic horror. It is a Mythos RPG set during the Second World War, where you play a secret Allied organisation fighting cultists, mad scientists and Deep Ones. It began as a setting for Call of Cthulhu and Savage Worlds before moving to Modiphius’s own 2d20 system. In that system you roll two twenty-sided dice, and lower results are better, and you can add extra dice by paying resources or accepting abstract risks.
The designers say openly that this is a pulp game. The 2d20 edition leans toward action, with cosmic horror treated as a threat to overcome, even if only briefly, rather than a terror that cannot be confronted.
- Complexity: Medium. 2d20 is a full system with its own resource economy, and it is heavier than a d6 pool. It is also used across other Modiphius games, so fans of those will find it familiar.
- Tension: The lowest of the three, but a different kind of tension. It comes from missions, enemies and risk rather than creeping dread. If you want the sense that you can’t win, this isn’t it.
Side by side
| Call of Cthulhu | Arkham Horror RPG | Achtung! Cthulhu | |
|---|---|---|---|
| Publisher | Chaosium | Edge Studio | Modiphius |
| Core dice | d100 (percentile) | d6 pool | 2d20 |
| Horror mechanic | Sanity points | Horror dice | Cinematic, pulp-leaning |
| Investigator toughness | Fragile | More capable | Heroic |
| Rules complexity | Moderate | Lower | Moderate |
| Dread level | High | Medium | Lower, action-focused |
| Best for | Mystery and doom | Newcomers, mixed groups | WWII pulp adventure |
Which one should you pick?
- Pick Call of Cthulhu if you want the purest horror experience and don’t mind losing characters.
- Pick Arkham Horror RPG if your group is new to roleplaying, likes board game components, or wants a gentler on-ramp to the Mythos.
- Pick Achtung! Cthulhu if you want Lovecraft with tommy guns, secret agents and a war to fight.
Our verdict
These games aren’t competing on the same ground. Chaosium owns dread, Edge Studio owns accessibility, and Modiphius owns action. For tabletop gamers coming from wargames and skirmish games, Achtung! Cthulhu will probably feel the most familiar. For a first evening of real horror, we’d still start with Call of Cthulhu.
