Voice actor time! Whee!
How did I EVER think this show was any good? Oh man.
But anyway, Koji is voiced by Hayami Sho, who also does Ashram, Wolfwood, and Muraki, and who I confuse with Nakata Jouji, who does the Count, Alucard, Hijikata, and Folken. Though I think I like Nakata Jouji a little better.