Illwinter Game Design is the name of a small software company in Sweden composed of Johan Karlsson and Kristoffer Osterman.^[1] The company was started in the 1990s under the name Bogus Game Design, but later changed its name. Registered officially as Illwinter since September 18, 2001,^[2] the team's product catalogue includes two long-running series of fantasy strategy games: Conquest of Elysium and Dominions. Illwinter's games are characterized by large amount of content, depth, lasting playability, support for multiple platforms (Linux, Mac OS X, Solaris and Windows included), good multiplayer support and simple visual and sound effects. Labor division within the tiny team is simple: Kristoffer Osterman creates the units, spells and descriptions, while Johan Karlsson makes everything else work.

Both Johan Karlsson and Kristoffer Osterman have expressed their love for role-playing games, especially Ars Magica and roguelikes. Kristoffer Osterman teaches religion, math and social sciences as a primary occupation.