Gravis had everything already planned out.
First, purchase some weapon forging techniques from the humans with Immortal Stones.
Second, sell these weapon forging techniques to the beasts for ore and Law Comprehension Fruits.
Third, sell these ores and Law Comprehension Fruits to humans for Immortal Stones.
Then, everything would repeat itself from the beginning.
This plan required some initial capital, but after that, basically everything would pay for itself.
Gravis would only need to look on as Siral, Stella, and Liam sold the stuff.
Of course, his employees wouldn't do this for free. Every employee of his would get to keep 10% of any trade. The profit margin was far, far more than just a mere 10%, which was why Gravis could be so generous with his pay.
All of his employees would earn a ton of money by only talking to some people and beasts.