Rise of the Kasai

You will probably get this trophy without even trying but if not load the Vaitaku level and choose Baumusu as your character. Press and select the bottom weapon, which looks like an upside down triangle. To ensure that you have the correct weapon equipped, press the right side of the then select Moves List and at the very top of this combo screen is the name of the weapon you have equipped which should say Narga. Now that this is done, use this weapon to kill every enemy that you come across. There will be way more than 50. The trophy will unlock immediately after killing the 50th enemy with this Narga.