A seclusion is an area of the Silent World where trolls and giants are known to nest. These are often in the ruins of the old world.

The major seclusions seen thus far are the areas around the old-world cities of Nokia and Tampere, Finland. The Paddlewheeler crossed through this area on the Keuruu-Pori Waterway (link to SSSS). During the travel, the ship's lights were switched off and the window shields were closed. On board, crew and passengers were instructed not to speak or make any noise, for fear of attracting beasts. Fortunately, the passenger vessel includes safeguards against potential noise.

It can also be assumed that the Mora-Öresundsbro route the Dalahästen passes through is also a seclusion, as there are many ancient ruins seen along the route as well as nesting trolls and giants (not by the passengers, of course). The sealed nature of the train car - having no lights or windows - is meant to keep what is inside the train away from what is outside. Still, it is not a perfect system, and traveling through a seclusion has certain hazards.

Page 86 (link to SSSS) has been edited in March of 2015 to replace the term "seclusion" with "exclusion", the former term still appearing on arc 1 page 84 (link to SSSS), though. It is not quite clear which one will be the authoritative one.