Hiro, Kyoushiro, Gin, Akatora, Akame, Hiyan, Giyan, Daisuke...and plenty more!
Naoki
Some popular Japanese boy names include Hiroshi, Yuki, Takashi, and Daiki. These names often have meaningful or symbolic elements, such as representing nature, virtues, or historical figures.
Indigo Som has written: 'No one to call home girl' -- subject(s): Artists' books, Chinese, Feminine names, Names, Personal, Personal Names
shikamaru, like from naruto :D
astro boy, gigantor and godzilla.
Here's a site for baby names, this is the A-Z of Japanese names. It also shows the meaning which I think will by useful to you. babynameguide.com/categoryjapanese.asp?strGender=&strAlpha=A&strCat=Japanese&strOrder=Meaning
Kenji means second son, Ichiro is a somewhat common name.
Som means stag. It is in some last names. For instance my friend's last name is Som de Cerff and her last name means "stag of deer".
By main characters, I think you mean the player characters. If so, yes, they have names. The boy is named Hilbert, and the girl is named Hilda. Their Japanese names are similar as well. The boy's is Touya, and the girl's is Touko.
-Kun is mostly at the end of boys names. Example; Hiroto-kun (Boy)Sorry for not explaining at properly.
Japanese Boy is a song by Scottish singer Aneka.
Japanese Boy was created on 1981-07-10.