Sano Manjiro in Tokyo Revengers is called Mikey. It comes from an English name Michel. Japanese pronounce it MA I KE RU and Manjiro shortened it into MIKEY. It’s a nickname Manjiro gave himself.
But he’s pure Japanese, isn’t he?
Yes, Sano Manjiro is a Japanese. The reason he made this nickname is Ema.
Ema is Mikey’s half-sister. Her birth name was Kurokawa Ema, but her mother abandoned her and left her to the Sano family. Ema was adopted by the Sano family and became siblings with Manjiro.
Her name Ema sounds like a foreign name in Japan. That annoyed Ema who was still little and depressed by parting from mummy. Mikey found that and declared “I’ll be Mikey from today.” to cheer her up. If an older brother’s name is also foreign-ish, Ema’s name doesn’t sound odd. Manjiro thought so and called himself Mikey to make Ema smile. That’s how Mikey was born.
If you want to know what Mikey’s real name means, check out the link below. You’ll learn what his Kanji characters stand for!