Rash Panzer can be found in the 2nd Paradise of Heaven within the Midnight Channel. It is a physical attacker, which will alternate between attacks and Power Charged attacks. After being defeated, it may drop a Steel Barrel. Selling 2 Steel Barrels will unlock the Raging Bull handgun for Naoto Shirogane in the shop.
In Golden, it is found at Paradise 2 to 4. It may drop Buffalo Stone for trade at Shiroku Pub.