Just from this alone, Rex now has a new way of gaining gold.
Knowing that back then Devo can sense lightning elemental stones even if they were inside the ground or well-hidden, he instantly knows that he can make use of Devo's senses and possibly also Amanir's senses to search for an immense amount of mana stones.
Rex remembered how easily Devo managed to do that, so he was quite hopeful.
[What do you need our help for?]
[I'm not going to help if I don't gain anything in return]
