The main male protagonist. A retired soldier who joined the Pumpkin Scissors to aid in their war relief effort. He was part of the secret 901 anti-tank-trooper unit, which basically consisted of foot soldiers trained to take down enemy tanks by themselves.
This unit, known also as the "Gespenster Jäger" (German for "Ghost Hunter") was part of the "Invisible 9". They are specially trained to ignore pain and fear in order to engage tanks and armored vehicles at point blank range. While the division was secret, all tank crews were warned to be wary of soldiers carrying a blue lantern.

Due to his reckless style of combat brought on from his conditioning/training to ignore pain and fear, Randel is frequently hospitalized during the series.

Character:
Despite his impressive stature (probably over seven feet) and a body riddled with scars, Randel's nature most of the time is kindhearted and ingenuous. But when he is in trouble he turns on his blue-steel lantern marked "901-ATT" and becomes a fearless and vicious combatant.
He is capable of defeating even heavily-armored foes with his 13 mm anti-tank gun, known as the "door knocker" (highly reminiscent of a Thompson Contender pistol).
Later shown to use another weapon which is a giant pair of shears, flashbacks showed it to be used to rip apart the metal plating armour of tanks to get to the pilot crews.

Source:WIkipedia