The Metal God Method devised by Cynthia sounded incredible.
It fit Vulcan's conditions and needs to an impressive degree. Even in ancient times, it was a luxury for a True God to expend her full effort into tailoring a cultivation method for a single individual, especially one that had a lot of special needs.
The only truly outrageous part was that Vulcan most likely had to pass four insane challenges in order to complete the final and ultimate stage of the new cultivation method!