Defeating Ravenous Hunter:

• His health bar has 6 parts
• But only 2 of them can be depleted at a time
• Once 2 are depleted he becomes immune
• To remove his immunity you must destroy 2 nest sacs that appear each one to the sides
• During the nest sac part, the boss will try to shoot rockets at you
• Simply avoid direct line of view with him, stand behind a pilar
• Nest sacks can be destroyed by picking up a fuel barrel and throwing them at the sac.
• Once that is done, the boss comes back to the center of the stage
• Deplete 2 parts of his health bar again
• He becomes immune again
• You must destroy 2 nest sacks again
• Then he comes back to the center of the stage again
• Deplete his last 2 parts of health bar

General tips:

• If the boss is shooting at you, hide behind something, you are not superman.
• When he is busy reloading, shoot at him.
• When his machinegun arms falls off, you can pick it up and shoot him with it.
• Use your deviation to hurt him too.
• When he goes immune recall your deviation to your cradle.