Yamato is a Student at the NEVEC Advance Base on E.D.N. III.
Yamato is very energized and motivated in VR missions, he is also always seen armed with his shotgun except when it is confiscated by Walter and returned in an optional side mission and oddly enough later in actual combat he is running around unarmed.
Yamato means Japanese spirit, it is also the name of a famous Japanese war ship and comes from the name of a location in ancient Japan.
Yamato's shotgun (as well as every shotgun) is based on the SPAS12 shotgun from modern day.
Yamato also looks similar to the hero Solid Snake of the metal gear solid series and is seen hiding in a box in the manga.