Haiyang shook his head and said, "If the manufacture of this airship were so simple, it wouldn't be considered a treasure by Goblin Masters. First of all, a structure of such a huge size flying at high speeds in the air has to withstand enormous impact and pressure, which sets a very high standard for the defensive requirements of the Zeppelin airship. To tell you the truth, the internal skeleton of this Zeppelin airship is completely cast from Kongou essence (diamond essence), extremely solid, and the outer skin is made from giant dragon hide, consuming the hides of five Giant Wind Attribute Dragons. And that Central Formation, the core of the flight control system that can be operated by ordinary people, is made using two rare metals, Demon silver and Krypton Gold, in addition to the three Ninth Rank Wind Attribute Magic Crystals."