Kuro-chan

The most strongest, violent cyborg cat. He was once an ordinary cat until after getting involved in an accident. He was then turned into a cyborg by Dr. Go, whom wanted him to stay with him under his command. However, Kuro rebelled and took down some of the doctor's minions.

He created a rivalry with Mi-kun, who taught him how to use a longsword.
Eventually, in the middle of the series, he became comrades with Mi-kun. Later on, Kuro defeats Dr. Go and becomes friends with him.

Despite his scary and violent attitude, he still shows signs of kindness to someone which includes the two old geezers who took care of him and Nana, a cyborg created by Kotaro, who fell in love to him. He may be pissed whenever she is around but he still cares and worries to her and probably fell in love to her too.

Kuro-chan can use a long range gattling, a revolving gun, a longsword, and his most ultimate form is the Hyper Berserker Kuro (真・暴走クロちゃん, Shin Bousou Kuro-chan).

Kuro-chan makes cameo appearances in the Robot Poncots manga and video game series. The Medarot S: Unlimited Nova mobile game has a collaboration event with Medarots based on Kuro-chan, Mi-kun, Matatabi, Dr. Go, and Neko Danger.