"Credits," He answered. To upgrade the missile defense system to Mythril grade, he might need a lot of credits.
But then, why couldn't he just go with choosing the Mythril grade weapon? Mark knew that the system will follow the law of fairness. It means that this random weapon he is going to receive will be worth less than 100 million gold coins for sure.
However, in his opinion, the current Crystal-grade missile defense system is far more worth than a mere 100 million as he could kill everyone under the Demigod realm with ease. Once it is upgraded to Mythril, perhaps, he might be able to kill even Demigods.
If that's the case, then, what will be the new worth of the weapon? Mark estimates that it will be atleast a billion. That would mean that its worth will be equal to the combined worth of all the empires that existed on the planet he was currently living in.
Logically, he believed that his decision is right and proceeded with the trade.