Why do you think Mayuri was not raised to be a shinigami? This sounds really interesting!
// If you want to know the full story, you’re more than welcome to read my heacanons page, which is located here.
For the short version, Mayuri was never a Shinigami to begin with, and only joined the ranks of the Gotei 13 when Urahara invited him to the 12th Division. For the most part, Mayuri was a criminal that was locked up underneath the 2nd Division jailcell.











