Date of birth: unknown
As he is the same age as Shion he was presumably born in 2001. (Age 16)
Blood type: O
Height: 178 cm (5'10")
Weight: 63 kg

A fugitive who is on the run from the police after escaping from prison. He sneaks into Shion's house after being shot. Nezumi gets treated and sheltered by him for a night, then disappears without a trace in the morning.

He hates No.6 and appears to know something about the city that no one seems to know.

Appearance
He has dark blue hair and wears it in a short, but visible ponytail, leaving his fringe and strands of hair hanging at the sides of his face. His eyes are a light grey. In episode 2 of the anime, he wears a cloak with a hood (made of superfiber) which he soon took off to cover the enemy's eyes temporarily before holding a knife to his chin. He also used it to cover Shion and himself when they jumped out of a car(also in episode 2). He noted that he is taller than Shion, to which Shion agrees due to it being a valid fact. He wears grey pants (he tucks in the left side into a boot and the other is left as is and appears tattered), a dark green jacket with multiple pockets and a notably big scarf around his neck. He has a fairly muscular body.

When he was 12 years old, his hair was slightly shorter than when he turned 16 and he left it down. He wore a gray over-sized shirt with a wide collar and a pair of dark gray shorts. His weight was 37.1 kg and his height was 145.3 cm.


Personality
Nezumi is a rude and straightforward person. He has a deep hatred towards No. 6. Though deemed a criminal in the beginning, he seems to be an honorable person
as shown when he saves Shion to repay him for saving himself back when they were 12. He is smart and quick-witted, easily able to defeat 4 officers of the safety bureau and steal their car. It is implied that he created the robot rats in his home which seem to be intelligent enough to follow instructions.

It is revealed in episode 8 that Nezumi is the sole survivor of the forest people. His deep hatred toward No.6 is due to his Forest Home burning down.
(Source: No.6 Wikia)