The Eelfinn and the Aelfinn, the snake- and fox-people, are not evil, just extremely strange; "They are not evil in the way the Shadow is evil, yet they are so different from humankind they might as well be."(TSR, 466) Their realms defy the laws of physics, and the presence of ta'veren cause some sort of instability within them. They seem to derive pleasure from sniffing people’s memories, and give things in return. Somehow they can see the Pattern, or at least, the Eelfinn can for sure. The Aelfinn, or fox-people, are untrustworthy and cruel.

Access to the realms of the Finn can be gained through the pair of twisted doorframe ter'angreal located in the Stone of Tear and Rhuidean (TSR). The Tower of Ghenjei is another entrance to their realms. Once entered, especially in the World of Dreams, it is very difficult to leave. Perhaps it is like a vacuole or one of those worlds running parallel or across the Pattern of the 'real' world.

A person entering the realms of the Eelfinn through the ter'angreal are permitted to ask three questions which the snake-people are required to answer. Visitors to the realm of the Aelfinn can make wishes which the fox-people grant, but they exact a heavy price in return.

There is a popular game, which is impossible to win (unless you cheat), called Snakes and Foxes. The rhyme each player must chant before playing is: "Courage to strengthen, fire to blind, music to daze, iron to bind." These items (apart from courage) are not permitted in the realms of the Finn - those entering are asked if they carry torches, lamps - any means of creating light, musical instruments or anything made of iron. This appears to be the terms of some agreement.