"Heavenly Spirit Ships are the product of ancient Grandmaster Artifact Refiners who combined mechanical techniques, artifact refining, and talisman patterns. Of course, the earliest Heavenly Spirit Ships were used for warfare, and nearly every one of them was a terrifying war machine."
"Heavenly Spirit Ships are classified by their size and capabilities into different grades such as Soldier Grade, General Level, Commander Level, and King-level. To my knowledge, the initial rates of speed for Soldier Grade, General Level, and Commander Level Heavenly Spirit Ships are two thousand, three thousand, and four thousand li respectively."
"The initial rate of speed for a Heavenly Spirit Ship refers to the speed it can achieve using Low Grade Spirit Crystals as a power source. When powered by a higher grade of Spirit Crystals, the speed of the ship can double."