In Sekiro: Shadows Die Twice you will be given a choice in the game at which point you will change the game completely. Everything you experience in the game after this choice will be different. Upon collecting the three pieces for the Incense you will be given the choice by your father to “Obey the Iron Code, forsake Kuro” or “Break the Iron Code, stay loyal to Kuro.” This guide will explain what happens depending on which one you choose.
Forsake or stay loyal to Kuro
When you try to return to Ashina Castle to speak with Kuro after you’ve gotten the final piece of the Fountainhead Incense you will notice that fast travel is turned off. The closest you can get to Kuro is to head to the Abandoned Dungeon. You will need to travel up the roofs to the spot where you once fought Genichiro. There you will find the Owl and Kuro. The owl is your father and he makes it clear that he wants you to betray Kuro and urges you to Obey the Iron Code.
If you choose to forsake Kuro at this point there is a story sequence that you will see and then you will fight two unique boss fights. This is effectively the end of the game and once these fights are complete you will be moved into New Game +.
There is still a lot more to Sekiro Shadows Die Twice. If you want to see the true ending you will not betray Kuro and you will continue on your mission. We won’t spoil exactly what happens from here, but there is more game to play so you may not want to betray Kuro and cut the game short. Of course, you can see both sides of the story in New Game +.
You will be forced into a boss fight with the Owl (your father) if you choose to stay loyal to Kuro. There is no return from this decision once it is made.