He's likely shown in 1:36 of the ten minute trailer. The famous strategist of the Shu Kingdom during the Three Kingdom war in China is often portrayed with a white fan, just like the guy in 1:36.
Also, he's blond. Weren't Odessa and Mathiu also blond? And didn't they have a brother that went missing? I see a connection here.
In Suikoden games, the strategist usually stands by the hero during important meetings of all the stars. In 6:57, when everyone says "warera ni shouri wo," the blond guy is right next to the hero.