Rogier's quest in Elden Ring is pretty easy to miss. You can first encounter this NPC in Stormveil Castle where he'll sell you sorceries, though you can't progress his quest until you've defeated Godrick the Grafted.
It's not a particularly long quest, but it is missable, and you won't be able to complete it if you speak to Ranni before reaching a certain point in his story arc. If you do happen to miss it on your first playthrough, don't worry. This quest isn't attached to any endings, but you'll miss out on a fair bit of lore-related stuff if you decide to skip it. So without further ado, here's how to complete the Elden Ring Rogier quest.
Elden Ring Rogier quest summary
Here's an outline of the steps to complete Rogier's questline. The first four steps may be optional, but you'll miss out on a chunk of lore if you skip them.
It's also worth pointing out again that speaking to Ranni before Rogier sends you to meet her will prevent you from finishing his questline.
- Find Rogier in the chapel at Stormveil Castle
- Speak to him at Roundtable Hold after defeating Godrick
- Return to Stormveil and interact with a specific bloodstain
- Speak to Rogier at Roundtable Hold then talk to Fia in secret
- Complete the Black Knife Catacombs in Liurnia to get the Black Knifeprint
- Give Rogier the knifeprint, then talk to him again
- Work through Caria Manor and speak to Ranni at the Three Sisters
- Tell Rogier what Ranni says, back at the Hold
- Return to Ranni and become her vassal
- Return to Roundtable Hold to complete the quest
Elden Ring Rogier location in Stormveil Castle
Rogier is found at the chapel in Stormveil Castle. To get to him, clear out the fire-throwing birds from the ramparts next to the Rampart Tower Site of Grace, then make your way down the steps on the right and onto the roof ahead. You should see another roof just below you, again on your right, so drop down here and head through the open window to your left.
You're now inside the chapel. You can find Rogier next to the altar on your right, so talk to him and exhaust his dialogue. He'll also give you the option to buy sorceries.
You can now continue working your way through Stormveil and defeat Godrick the Grafted. Once you've taken care of your first Shardbearer, return to Roundtable Hold and you'll find that Rogier has relocated to the balcony overlooking the large hall. Talk to him here and exhaust his dialogue again and he'll hand over the Rogier's Rapier +8 weapon.
To progress further, you'll need to return to Stormveil and uncover clues as to what happened to Rogier.
How to get to the bottom of Stormveil
You'll need to take out a mini-boss for this next step, but first you need to get into the bowels of the castle. From the Liftside Chamber Site of Grace, head out the small door to the west. If you haven't unlocked this yet, this video will walk you through it.
Once outside, head towards the door opposite but instead of going through, use the broken rooftops on the left to get down to the floor below. There are a couple of bats here so deal with them, then use one of the beams to reach the wooden platform on the other side. Keep dropping down until you reach the bottom.
Make your way through the statues and debris—watching out for hidden rats—and you'll come to a drop off. Make sure you're ready to fight a mini-boss before dropping down again.
Once defeated, head to the back of the large chamber to find the absolutely horrific thing that Rogier must've confronted and interact with the bloodstain to find out what happened. You can now fast travel back to Roundtable Hold to speak to Rogier once more.
Where to find the Black Knifeprint
When you speak to Rogier after returning from Stormveil, he'll tell you about the Night of the Black Knives and that he's been researching what happened. Make sure you exhaust his dialogue here.
Now go and speak to Fia and agree to let her hold you. Choose the option to “Talk in Secret” and she should shed some light on Rogier and will mention a Black Knifeprint. She will hand over the Knifeprint Clue item to give you a lead on where to find it. The item is a map that shows the location of the Black Knife Catacombs in Liurnia, so that's where you need to head next.
You can find the Black Knife Catacombs on the eastern shore of Liurnia, far up north and at the end of a narrow pass. These catacombs actually have two bosses, and it's the Black Knife Assassin that drops the Black Knifeprint. If you've spoken with D at all, his summon sign should be there to help you with the fight.
Once you've obtained the item, return to Roundtable Hold and hand it over to Rogier. You can reload the area by resting the table, then return to Rogier and speak to him again and he'll tell you what he's discovered from the Black Knifeprint.
Now you need to go and meet Ranni at the Three Sisters.
Now it's time to track down Ranni
Now you need to go and meet Ranni at the Three Sisters. To do this, you'll need to work your way through Caria Manor in the northwest corner of Liurnia and defeat the boss there. You'll find three towers behind the manor and the middle one is home to Ranni the Witch, who has her own complex questline.
Ranni will tell you to leave when you speak to her, so head back to Roundtable Hold and speak to Rogier again. He'll suggest you enter Ranni's service to find out more information. So return to Ranni and speak with her again, and she'll accept you as her vassal. You can now continue with Ranni's quest as normal.
Complete the quest
Finishing Rogier's questline
Return to Roundtable Hold again and speak to Rogier and he'll tell you he's feeling tired and if you reload the area, he'll be asleep.
Once you reach a certain point in the story, you can return to Roundtable Hold and collect Rogier's Bell Bearing, and the Spellblade armor set. The trigger for this is unclear—it may be once you reach a certain point in Ranni's quest or when you kill the boss at the end of Fia's quest.