If you're looking for the character, he is not in the game currently. If you are searching for the nano, Van Kliess is the Unstable Nano; he was scheduled to be put in as a full-fledged nano with mission, but due to Fusionfall not updating since, oh, OCTOBER 2011 (seriously, Cartoon Network? Seriously? That's your service with this game?), the Van Kliess nano does not exist; he currently appears as a blank space in the nano booklet.