Lore question.

[Panpan2019]

Okay, I am not normally in the dark about the lore, the lore of all the other FromSoft games I have played makes sense, but Sekiro is confusing me a bit.

I have beaten Genichiro, and Kuro is telling me that we need the Mortal Blade to do Immortal Severance. I know the Mortal Blade is in Senpou Temple, and I'm trying to get there now. But why do I need to go to fountainhead palace and the sunken temple later on? I think there's something about a flower, but I'm not sure. I'm also confused about what EXACTLY Immortal Severance is, and why it needs the Mortal Blade.

[Kabirbd]

I will try to explain. It may be a bit rough as I didn't really watch lore videos.
As you know, Kuro the divine heir has the dragon's heritage which makes people basically immortal. That's the power Kuro gave you so you can come back. But repeated death & resurrection causes stagnation. So other people or npc get sick. Emma even mentions that a lot of people died in the past because of it.
So what is Immortal Severance?
Kuro wants to remove the dragon's heritage or basically sever immortality & stagnation.
Why do you need to go to fountainhead palace?
Kuro found a book which mentioned a previous divine heir who also tried immortal severance which requires item found in fountainhead palace or divine realm.
Why do you need to go to sunken valley?
To get to fountainhead palace, you require certain key items, one of which is in Sunken valley which is a flower. There are other items which you will find on your own or Kuro will give you hint.
Why do you need mortal blade?
For 2 things. One is to kill the undying & infested enemies.
Other is that you need blood of divine heir. Except the divine heir can't bleed. So you use the mortal blade to take a blood sample basically. You also require the blade for an additional thing which is directly related to the ending so I won't say that.

[Panpan2019]

Originally posted by Kabirbd:

I will try to explain. It may be a bit rough as I didn't really watch lore videos.
As you know, Kuro the divine heir has the dragon's heritage which makes people basically immortal. That's the power Kuro gave you so you can come back. But repeated death & resurrection causes stagnation. So other people or npc get sick. Emma even mentions that a lot of people died in the past because of it.
So what is Immortal Severance?
Kuro wants to remove the dragon's heritage or basically sever immortality & stagnation.
Why do you need to go to fountainhead palace?
Kuro found a book which mentioned a previous divine heir who also tried immortal severance which requires item found in fountainhead palace or divine realm.
Why do you need to go to sunken valley?
To get to fountainhead palace, you require certain key items, one of which is in Sunken valley which is a flower. There are other items which you will find on your own or Kuro will give you hint.
Why do you need mortal blade?
For 2 things. One is to kill the undying & infested enemies.
Other is that you need blood of divine heir. Except the divine heir can't bleed. So you use the mortal blade to take a blood sample basically. You also require the blade for an additional thing which is directly related to the ending so I won't say that.

Thanks a lot! This helped very much understanding the story. Now matter how many of their games I play, its still amazing how elaborate FromSoft's stories are!