Folken is Van's older brother who was heir to the throne, but was unable to defeat the dragon. His right arm was ripped off and he chose not to return to Fanelia because of the shame of failing. He met the emperor of Zaibach who gave him a nasty looking mechanical arm. He believed in what Emperor Dornkik wanted to do and so became his first officer. Volken tried to convince Van to join him, but instead Van blamed what happened to Fanelia on him and swore him to be a mortal enemy. Volken's love interest are two cat girls Naria and Eriya. Mostly it's just them worshipping the ground he walks on (what is it with these Fanelia boys and catwomen?!) Despite his alliances with Zaibach, Folken is a very caring person for those less fortunate than him. He'd rather be the diplomat to achieve what he wants than to go into senseless slaughter like Dilandau. He's a very brilliant man He created most of the advancements in technology which made Zaibach such a daunting enemy. Folken is far more verbose than Van who doesn't really talk as much.
On to more (spoiler!) info and (spoiler!) pictures - warning: this contains spoilers!