Marais is an island and country on Aeo, and the setting of Blood Trance. It was the first country invaded and taken over by the Kresthitan Empire. Originally Marais was a part of Aereus but they were separated in a magical accident.
- Archoeia: The capital city of Marais, and the home of the well-known Scirevicis Academy.
- Mallowmont: A small fishing village.
The Scarlands is an area in the north-east of the island, at the site of the explosion which separated Marais from Aereus in the year 500BFC. The entire area is saturated in radioactive magical energy from the explosion, and as a result is barren and devoid of all plant life.
The main food produced in Marais is crab meat; crabs are the most common wild animal found on the island. Crab meat also makes up a significant portion of the country's exports, as crabs are much less common in Aereus and Kresthita.