After five years of living as an adventurer
However, now that he finds himself lost in a previously limited realm rich in supernatural essences, does he really want to return to his old world? If nothing else, plagiarism-ahem, it should be fun to learn new spell structures by watching local mages. Sure, he'll face new dangers in this strange world, but they won't be anything that any fancy spell can't fix.
While he may have been confused by this "cultivation" business of the local mages and their lack of appreciation for the details of essence manipulation, he discovered that perhaps there were hidden depths in their art that neither party was fully aware of.