I am planning out my campaign's first BBE and am going with an aboleth.

In the rules an aboleth has a number of regional effects that reach up to a mile. This aboleth is currently in an underground pool in a mine about a mile underground. So would the characters see any evidence of the aboleth effects at ground level away from the mine, or would the effects only exist in a bubble the top of which is level with the top of the mine?

To my mind the effects will be a bubble, so widening out from the aboleth, if the approached underground they would meet them far sooner?


2 Answers 2


RAW it's a sphere

Simply because the simplest reading of 'within one mile' is that it's the union of every point that's less than a mile from the creature's lair. A cylindrical area of influence would be an exception, and it's not an exception that's specified.

As others have suggested, this distinction is far from critical and the game will not suffer if you use your judgement to create whatever experience is most engaging for your players.

  • 3
    \$\begingroup\$ Bonus question: is it one mile from the Euclidian centre of the lair, or one mile in any direction from every point on the perimeter of the lair? \$\endgroup\$
    – Lovell
    Jan 24, 2021 at 18:38
  • \$\begingroup\$ or is it in relation to the aboleth and moves with it? \$\endgroup\$
    – Joshua
    Jan 25, 2021 at 4:32
  • \$\begingroup\$ @Joshua it's not - Regional Effects are 'within 1 mile of the Aboleth's Lair' \$\endgroup\$
    – Lovell
    Jan 25, 2021 at 9:47

Big Bad Regional Effects are world building tools to be used however you like.

Regional effects are not rules in a rigid sense. They are tools to be used at your discretion to shape the world around your Big Bad. It doesn’t matter if you interpret the “range” as a column or sphere. It’s just a suggestion. Use it to build your world.

The introduction to the Monster Manual expresses this idea nicely, in the section “How to Use these Rules”:

The best thing about being a DM is that you get to invent your own fantasy world and bring it to life, and nothing brings a D&D world to life more than the creatures that inhabit it. You might read a monster’s entry and be spurred to create an adventure revolving around it, or you might have an awesome idea for a dungeon and need just the right monsters to populate it. That’s where the Monster Manual comes in handy.


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