The protagonist of Suikoden II is Riou, who goes from being a member of a youth brigade in the Highland Kingdom to being the leader of its opposition, the New Alliance Army. In acquiring one half of the Rune of the Beginning, he is destined to become leader of the newly rebuilt Jowston Army, and also to oppose the holder of the other half of the Rune of the Beginning, Jowy Atreides.
The antagonist for the majority of the game is Luca Blight, heir to the throne of Highland. Luca is a bloodthirsty madman who developed a strong hatred for Jowston at a young age after witnessing his mother's rape by thugs hired by City-State capital Muse to attack the Highland royal envoy.
A variety of characters from the original Suikoden appear in Suikoden II. Some such as Viktor play major roles in the story, while others only appear in cameos (such as Kage who is briefly seen talking to Jowy before Mayor Anabelle is killed). If data from a Suikoden I saved game file with all 108 characters recruited is loaded, the first game's protagonist Tir McDohl can be recruited. List of recurring characters in Suikoden has a comprehensive list of all characters who span multiple parts of the series.