From The Heretic Knowledge Vault
This rather unsavory fellow is a Tsuirakuan mage of more than average power, and apparently, also more than average avarice. PC Argus Cleiviein knows him from their days interacting in Tsuirakushiti before Argus got exiled from the sky city, before the game started. His memories of the man, to put it mildly, are not warm. Let Argus tell it himself:
"Arsoro Kurou is one of the scariest men that I have ever met. That should tell you something right there. He's a scholar, specializing in anthropology and archeology. His interests are the secrets of the past.... No," Argus stopped himself. Best to be honest here. "His all-consuming lust is for the secrets of the past, whatever they may be. The man is a genius. Whatever he has an interest in, he excels at. I hate to admit it, but if he had devoted himself to my field, Kurou would almost definitely have surpassed me." That was painful to get out, but might as well be truthful.
"Kurou isn't much to look at. Small, scrawny. Fairly plain. Comes across as pleasant and cheerful, and well-spoken. I wouldn't call him urbane, but certainly cultured. He has a very distinctive smile, gentle and calming. I saw him murder a man in cold blood with that same smile on his face. It didn't even flicker." Argus shuddered at the memory. "His eyes aren't dead... they have this light in them, that's sort of like a cold light. If there's an opposite to a soul, that's what reflects in Kurou's eyes." He looked at everyone.
"Basically, Arsoro Kurou wants to know. He wants to know for the sake of knowing. And if you're in his way, he removes you. Just like that."
The menacing Dr. Kurou enters the story of Errant Road in or near the small town of Gervasiel, where Argus and the other members of his party (Sister Rose, Lillith, etc.) have a small errand to do involving a curious artifact that has been found in ruins near there. Entirely consistently with his personality as Argus describes it, Kurou has an interest in this thing too, which brings him into conflict with the party. Drusia Valis, a Peregin (and PC) who's part of the party, decides to use her considerable feminine wiles first to find out what he's up to, then to engage him in a fight that comes close to being fatal to both of them. Both however manage to escape, Drusia back to the party for reassembly by Rose, and Kurou to parts unknown.
Later, and as part of the "background noise" of the game, Kurou links up with the similarly menacing Haniko Goto and the nasty elven ranger Bauti, who have their own reasons for wishing the party of adventurers no good. Courtesy of a very mistaken bit of analysis on Bauti's part, they go hieing off to parts unknown for a while, and while they're offstage, something happens that leave Kurou and Bauti cowed by Ms. Goto, who's showing signs of madness from the whole thing. The three co-conspirators were last seen in Haniko Goto's lair back in Tsuiraku, starting to plot their next moves, so we'll probably see Kurou (and the others) again.