-----
After Kamei acquired her Mana Core within a few minutes of having been suggested, Frank glanced at the pile of Mana Cores he had gathered, there were around fifty more left, although most of them were F-Rank, so the amount of world essence they could offer was small in comparison to higher Ranked ones such as those he got from Zero or the Giant Scorpion King Boss.
If he wanted for everyone to properly get to Rank 2, including his tamed monsters, the whole group would have to keep grinding a lot more, but they had months before they were to finally go to the capital, so Frank was confident that it could be a doable goal.
Alongside the Mana Cores, there were also other ways to increase Mana Core Cultivation, such as using Divine Power or App Points to buy items in the Dungeon Item List, which could be said to be a pseudo shop of sorts, although it was not intended that way when it was designed.