Aizen is a modern given name of Japanese origin. It goes back to Aizen Myoo, a Buddhist wisdom king whose name is written with the characters for "love" and "dye", and most American parents know it from Sosuke Aizen, the central antagonist of the anime and manga series Bleach. The name only appeared in US records in the 2000s, climbed from number 1848 in 2015 to a peak of number 1005 in 2024 and stands at number 1081 in 2025.