R'lyeh is an mysterious realm propagated by underwater telepaths, spanning all three ages. It may refer to:

• EA R'lyeh, Time of Aboleths → This one's telepaths are giant, competent, polyp-spawned fish!
• MA R'lyeh, Fallen Star → This one's telepaths are Mindflayer-like squid-folk from space, who have a summoning gateway!
• LA R'lyeh, Dreamlands → This one is similar to the previous one, but its telepaths have lost their constituents' minds.

All three have powerful Astral, dirt-cheap slaves of various kinds (even mages and priests), and unique mental-and-magical schemes.