Derek Jupiter is Iron Weasel's British, cocky, very selfish but fairly charming, handsome and hot lead singer and a character in I'm in the Band. He is known to be a very good magician as shown in "Magic Tripp" and can speak Spanish as seen Annoying Arlene and he can also speak Japanese as seen Happy Fun Metal Rock Time. He delivered a baby in the episode What Happened?. Vic Blaylock claims that Derek causes all the problems in the band, though Tripp claims that Derek is the heart and soul of Iron Weasel. He is also the tallest of the guys (Tripp, Ash and Burger). He admits to have his very own dungeon when Ash found a strange set of keys in What Happened? He can also play key board, as seen in Izzy Gonna Sing.