I don’t know if ACKS invented dynamic lairs (a raison d'etre for the otherwise ancient % In Lair), but ACKS is the first game in which I actually used % In Lair. I love dynamic lairs! In one of my earliest ACKS games, I created a “dynamic dungeon” consisting of a series of prepared encounters in a sprawling cavern complex. It worked fantastically well.
For some time now, I’ve wanted a list of all Autarch-published ACKS monsters. Compiling that list, I noticed a lot of monsters with “% In Lair: None” (see below). “Nooooooooooo!” I thought. I want “lairs” for all my monsters.
Many if not most of the % In Lair values are likely legacy values. Although I can see the logic of some monsters not “lair-ing”, I don’t agree with all of the list below. (Yellow Mold never appears in its lair, only as a wandering monster. Wait, what?) It may be the creative Judge in me, but I want prepared encounters with every monster that are more than “a monster appears.”
Therefore, I am now running “% In Lair: None” as “% In Lair: 5%.” The number of monsters in the prepared encounter will be the same as for a wandering monster encounter. At least to start with – more monsters may make sense for some monsters, perhaps even being the reason for the prepared encounter, e.g. a spot favorable for finding the monster’s food, bringing more than usual.
Monsters with “% In Lair: None” often have “Treasure Type: None.” However, not all. Most of those that do have treasure have “Incidental” treasure types (C, I, M, or P), often said to be found in their bellies. I think similar incidental treasure may be appropriate for any monster capable of swallowing (or killing in place) a human, such as a Tyrannosaurus Rex or Yellow Mold. Also, Treasure Type Q seems as appropriate for a Djinn or Efreet as a Frost or Fire Salamander.
Core rulebook monsters with "% In Lair: None"
Elephant Treasure Type: Special
Fish, giant, catfish
Fish, giant, piranha
Fish, giant, rockfish
Fish, giant, sturgeon Treasure Type: I
Gelatinous cube Treasure Type: C
Mastodon Treasure Type: Special
Men, merchant Treasure Type: J (per 10 wagons)
Purple worm Treasure Type: P x2
Sea serpent Treasure Type: M, I
Shark, great white
Snake, spitting cobra
Snake, pit viper
Snake, sea snake
Snake, giant python
Snake, giant rattler
Statue, animated, crystal
Statue, animated, stone
Statue, animated, iron
Toad, giant Treasure Type: C
Whale, killer Treasure Type: M
Whale, narwhal Treasure Type: Special
Whale, sperm Treasure Type: P