Originally Posted by NeoKakarott023
Btw, how does Mayuri know about the Quincy, and Juha Bach. Turn Back The Pendulum had him as a Pup to Kisuke, 100 YEARS AGO???!!!!
He probably found out through researching it. SS does have a pretty badass library. Aizen was able to figure out something like the Kings Key from reading hints about it from various books, so info on Juha Bach, and the quincy should be available too.
Also Mayuri told Ishida way back in the "rescue rukia arc" that he had done countless experiments on the quincy.