Mantle?
The "crust" in its name obviously refers to the Earth's crust according to its design, could it be possible that the "le" suffix refers to the mantle? - Swagmander 21:46, 3 March 2011 (UTC)
Actually, I think 'Crust' is short for 'crustacean' and is combined with 'Castle' because if the large house on it's back. Seems most logical to me. Thetool 07:59, 12 March 2011 (UTC)