note: Do not give Nepheli the potion that Preceptor Selivus gives when he is visited during Ranni’s quest line. It will end their quest line early.
Nepheli Loux is another Tainted encountered early in an Elden Ring playthrough. She works for her foster father, Gideon Ofnir, looking for ways to raise him to Elden Lord. Her quest line was impossible to complete until recently. After patch 1.03 it finally comes to an end.
The first part of the quest is to meet Nepheli near the Secluded Cell Site of Grace in Stormveil Castle. Run past the giant and into a small room south of Grace. She will stand over a dead exiled knight. Exhaust their dialogue and optionally summon them to aid in Godrick the Grafted’s boss fight.
Next, meet up with Nepheli at the Roundtable Hold after defeating Godrick. Speak to her near Gideon Ofnir’s study and then to Gideon himself by selecting “About Nepheli”. Listen to him, then talk to Nepheli again, making sure you’ve exhausted all of their dialogues.
Continue through the game until you reach Liurnia of the Lakes, then head to the Albinaurics village where you will meet Albus and receive the Haligtree Secret Medallion Right. Nepheli will kneel next to a pile of corpses under a bridge. Exhaust their dialogue here, and optionally summon them against the Omenkiller world boss to the north, past the flame-breathing perfumer enemy and Albus’ pot.
Return to the Roundtable Hold and go down the stairs near the Blacksmith Hewg. Nepheli will kneel to the left of the bottom of the stairs.
Exhaust her dialogue here, then talk to Gideon and select “On Nepheli’s Despair.” Return to Nepheli and speak to her again.
Now go to the Four Bell Towers and take the portal that leads to the Abyss of Anticipation.
Unless it’s already dead, defeat the grafted sprout for a sweet revenge and head back to the church you visited at the very beginning of the game. Take the stairs to the right of the door and find the Spirit of the Stormhawk King.
These are of no immediate use, so return to the round table again. Go back to Nepheli and talk until you get a chance to give her the Stormhawk King’s Ashes. She will say they look familiar and thank her for having them.
At this point, continue Kenneth Haight’s questline until he has returned to his stronghold and is looking for a rightful heir to Limgrave. Continue in the game until Morgott, the Omen King, is defeated atop Leyndell, Royal Capital.
Once Morgott is done, travel to Godrick the Grafted Site of Grace and head north into the Throne Room. Both Nepheli and Kenneth Haight will be there, with Kenneth noting that she has become the Lady of Limgrave and Godrick is out of the picture. As a reward, Nepheli will provide an Ancient Dragon Forging Stone for upgrading a standard weapon to +25.
https://www.gamepur.com/guides/how-to-complete-nepheli-louxs-questline-in-elden-ring-all-steps How to complete Nepheli Loux quest line in Elden Ring