The fourth game in the Gensou Suikoden series. It is the first prequel game of the series, taking place 150 years before Gensou Suikoden I. It takes place among the Island Nations, to the south of Gensou Suikoden I's Scarlet Moon Empire, during an invasion by the Kooluk Empire which was engineered by "Merchant of Death" Graham Cray, and follows exiled Gaien Knight Lazlo. Lazlo, following the usual Gensou Suikoden formula, becomes the host of a True Rune (the cursed Rune of Punishment) and the leader of the rebel military. Due to its location, travel and major battles in the game are carried out by ship instead of on land. It also has the fewest returning characters of any game in the series, with four characters from previous games who were already established as immortal being present.
Due to its simplified gameplay (especially the reduction of party size from the traditional six to only four), annoyingly frequent random battles, and a story that never really lives up to its potential, Gensou Suikoden IV is widely considered the worst in the series.