1. Equip the SVD sniper rifle and load it with incendiary rounds. DO NOT EQUIP THE SCOPE.
2. Position yourself in the corner of the rooftop facing the end. Do NOT move from this spot.
3. When The End begins his monologue, start walking towards the end of the rooftop. When The End shoots you the first time, start circling the rooftop while reloading your rifle. If The End shoots you a second time, immediately drop to the ground and crawl.
4. Continue circling the rooftop and firing incendiary rounds at The End. The incendiary rounds will set The End on fire, causing him to take damage over time.
5. When The End's health bar reaches 0, a cutscene will play and the battle will be over.
Method 2: Stealth Method
1. Equip the camouflauge suit, suppressor, and M1911 pistol with tranq bullets.
2. Sneak around The End's camp until you find him near the water. Be sure not to equip any weapons other than the tranq gun.
3. When The End's back is turned, sneak up behind him and press the "action" button to hold him up by gunpoint.
4. A cutscene will play, and The End will be defeated.