The term was used in Japan as a neutral alternative to kanai (meaning "inside the house"), which younger generations found outdated .
Videos like waifu.mp4 often categorize characters by personality "tropes" or archetypes : waifu.mp4
The anime Azumanga Daioh popularized the term in the West. In episode 15, the character Mr. Kimura drops a photo of his wife and refers to her as "mai waifu" . The term was used in Japan as a