Umino Shuuichi

Cousin of Yuuko and Suzuha who he treats as sisters.

Justice Blade 2
His fate depends on the route taken

if Yuuko is corrupted his disappears for quite some time and is not heard of only to reveal to be alive wishing to save Yuuko from Earth Jade he request Suzuha help without the rest of the new Justice Blade.

Spoiler

It's revealed that he was transformed into an Avatar known as Dark Dolphin and swore loyalty to Earth Jade.