Munin is Little Jack's trusty firearm that never leaves his side.  Its revolving bronze cartridge below the main body can be rotated to whatever setting Little Jack needs for the situation.  They include miniature missiles, lasers, stun ray, among others.  The cartridge can be changed for another with different abilities should Little Jack have a need for alternate ammunition.  Munin's sister gun, Hunin, went missing years ago when it was taken by one of Little Jack's former partners in the gang he used to belong to.