His involvement with the group was more of a scientist in training and data collector. When Sho was "destroyed" by Archanfel, he contiunes to collect various data on the Chronos Coporation in hope that one day when Sho returns they will have a wealth of experience that they could use against Chronos.

Plum and chubby, but a very serious individual at the later part of the series, most properly because he understands that he is no longer a kid anymore and he must fight to stay alive.

My Comments
A true friend. not everyone will stick by you when half the world is after your neck.
Tetsuro has the makings of a great scientist or reasearcher.