|Seiya Kumagai - 熊谷晴哉|
|D.O.B.||26th March 1977|
|Family||Grandfather: Genzo Todaka|
|Appears in||Shenmue I|
Seiya Kumagai (Japanese: 熊谷晴哉) is a young boy who lives in Yokosuka, as both his parents work late and he has difficulty making friends, he is often looked after by his grandfather, Genzo Todaka. He is very shy and won't talk to children his own age unless his grandfather is close by, and he refuses to talk to strangers. He does know Ryo though to some degree, so he will talk to him a little.