In Yakuza 3, there is a substory call "manga mania" where you meet an aspiring manga artist wearing a beret hat name "Tsutomu Hirano".
His dream is to become a professional manga artist, but his family want him to pursue a carreer in medical. It up to Kiryu to solve this problem.
It quite obvious that this character is a shout out to "Osamu Tezuka" aka "The god father of manga". Thanks to his medical experience, Tezuka was able to create the manga series Dr Black Jack.
And there are still people who think Y3 substory suck lol