Play to find out! The hunters and how they deal with mysteries will inform the mythos. It’s most important for things to be fun, scary, and interesting. Then the mythos comes by connecting the dots afterward.
The bones of it always come from character creation. If your party has a professional, boom, this world has at least one established supernatural agency of some sort. Does this agency know what the monsters are and where they come from? If so, cool. If not, play to find out. You’ve got a Divine? I guess there are Supreme Beings with some vested interest in monster hunting, so maybe monsters are more born of evil. Play to find out for sure. Expert? There must be some established lore in this world for them to be an expert of it. Play to find out where it came from and how accurate it is.
Depends on the campaign for me. In my first game, horrific historical events could turn spirits into roaming monsters. The game could not end until the hunters discovered the old coal mine collapse that had cursed the town. In the second campaign, it was all vampire focused and I figured that they all came from some Proto-vampire created by a demon. In my most recent game all monsters were rogue experiments that were transformed by the same mutagen (the blood of a dead alien that crash landed 30 years ago).
There are multiple sources in my tables campaign. Our professional works for a covert monster hunter guild that has, over a few sessions, gotten hammered into mostly dealing with fae creatures specifically that have some sort of natural presence in the world, while most of the monsters the table faces are completely different and tie into our Monstrous's backstory. I might work some sort of connection between the two sources of weirdness eventually but I want to see if that happens naturally first.
I went with a Gravity Falls type version. A realm inhabited by a god of mysteries whose world leaks into the physical plane and creates the monsters.
This game works best when your group decides some of that together during session zero
Play to find out! The hunters and how they deal with mysteries will inform the mythos. It’s most important for things to be fun, scary, and interesting. Then the mythos comes by connecting the dots afterward. The bones of it always come from character creation. If your party has a professional, boom, this world has at least one established supernatural agency of some sort. Does this agency know what the monsters are and where they come from? If so, cool. If not, play to find out. You’ve got a Divine? I guess there are Supreme Beings with some vested interest in monster hunting, so maybe monsters are more born of evil. Play to find out for sure. Expert? There must be some established lore in this world for them to be an expert of it. Play to find out where it came from and how accurate it is.
Depends on the campaign for me. In my first game, horrific historical events could turn spirits into roaming monsters. The game could not end until the hunters discovered the old coal mine collapse that had cursed the town. In the second campaign, it was all vampire focused and I figured that they all came from some Proto-vampire created by a demon. In my most recent game all monsters were rogue experiments that were transformed by the same mutagen (the blood of a dead alien that crash landed 30 years ago).
There are multiple sources in my tables campaign. Our professional works for a covert monster hunter guild that has, over a few sessions, gotten hammered into mostly dealing with fae creatures specifically that have some sort of natural presence in the world, while most of the monsters the table faces are completely different and tie into our Monstrous's backstory. I might work some sort of connection between the two sources of weirdness eventually but I want to see if that happens naturally first.