Most Rogue Cultivators would not have a large reserve of Spirit Stones. But to the five Tribes that once made up the great Crow Divinity Tribe, a Tribe which had passed down legacies for many years, well, Spirit Stones…
Were something they had a lot of!
They might not have enough to keep a large flying machine going for many years, but it would at least get them half way. After the arrival of the violet rain, the spiritual energy grew scarce to the point where it virtually didn't exist. Therefore, Spirit Stones, which were in fact an expendable resources, became the only way to replenish spiritual energy. Therefore, some were wasted in this way.
Thankfully, the fact that there were not many Cultivators in the Crow Divinity Tribes meant that the consumption was reduced by quite a bit. At the moment, there were plenty remaining. Currently, the main problem was how to acquire a large flying machine that wasn't powered by the spiritual energy of Cultivators.