IN THE SHADOW OF THE BLOODLINE
This quest becomes available during the Stop Ranrok and Rookwood main objective. Head to the Great Hall Floo Flame in the Great Hall to find Sebastian. Speak with him to learn a bit more about Ominis’ family. He’ll then part ways with you and mention that he’ll reach out when he has more information. This quest essentially kicks off the questline to learn the Dark Arts spells.
In the Shadow of the Study
After some time passes, Sebastian will send an owl post to meet him outside the Slytherin common room. Travel to the Grand Staircase area and make your way to the bottom level to find Sebastian. If he’s not there, wait for him to show up then speak with him. Follow Sebastian to Ominis’ location and speak with him to convince him to help you. You’ll then need to light 3 nearby braziers to reveal the entrance.
Head inside then follow the stairs down. You can find the 1st of Noctua’s notes on a ledge. After collecting it, cast Reparo on the broken image and then speak with Ominis. Head through the doorway to reach an area with a lot of locked gates. You’ll need to match the symbols on the gates under a nearby snake statue to open them. If you’re not fast enough, the statue will attack you. As you work through opening each gate, make sure to grab the other pages of Noctua’s notes. The last one can be found on the ground near the final door. Speak with Sabastian who tells you what needs to be done. Speak with Ominis then return to Sebastian. You’ll have three options: Sebastian curses you and you don’t learn the curse, Sebastian curses you and you learn the curse or you learn the curse and use it on Sebastian. Regardless of what you choose, all three options open the door.
Once in the room, grab Sytherin’s Spellbook under the head statue of Salazar then head up the stairs. Also, make sure to use Revelio here to find the Revelio Page. Give the book to Sebastian then grab the note on the desk behind him for a cool Harry Potter easter egg. Use the statue at the back of the room to return to the Slytherin Dungeon. Listen to what Ominis has to say then the quest will be completed.
In the Shadow of Discovery
After some time passes, Sebastian will send an owl post to meet him in the Undercroft. Travel to the Defense Against the Dark Arts Classroom Floo Flame then head to the Undercroft and speak with Sebastian there. You’ll then need to speak with Ominis after their little spat to complete the quest.
In the Shadow of Time
This quest becomes available after learning Transformation during the main objective, Stop Ranrok and Rookwood. Travel to the Feldcroft Catacombs Floo Flame the Feldcroft Region to find Sebastian nearby. Speak with him then enter the catacombs. Follow the path until you reach the room with spiders. Defeat them then look for a block you can use Wingardium Leviosa on. Move the block to the northwest side of the room to climb up onto a ledge.
There will be a collection chest here. Jump back down into the main room then proceed on heading southwest through the hallway. In the next room take left (heading east) down a flight of stairs. Defeat the spiders then continue down the stairs to the east. In this room, examine the note by the alter then speak with Sebastian.
Before you progress with the story, you can obtain one last collection chest. To reach this chest, start by blasting through some rubble on the northern side of the room to make a small hole you can crawl through.
Do so then follow the path until you reach an area with some Devil’s Snare. You’ll need to make a bridge using the 2 sets of bones in this area that are hidden in the tombs along the wall. Use Accio to pull them out and set them up!
Use Accio to open the door then follow the path to find the second collection chest! Pull the door knocker to the left of the gate to cause it to rise. This will give you a short cut to the alter room!
To progress the story, you’ll need to find 3 sets of skeletons to open the skeleton door Sebastian is standing in front of on the east side of the room.
One set of bones can be found found on the altar. The second set can be found by using Accio on the tomb in the wall on the southwestern side of the altar. To reach the last set, blast your way through the door on the southeast side of the room then use Accio on a tomb inside this small room.
Bring all the bones to the door Sebastian is standing in front of on the east side of the room to proceed. When you’re ready, head through the skeleton doorway. Once in the next room, Sebastian will offer to teach you the Imperius Curse. The choice is up to you. After declining or learning the curse, you’ll be attacked by a group of spiders. Defeat them then head down through the southern doorway (the northern path leads to a side room with some chests if you want to explore a bit).
For this room, there are four knockers you can pull using Accio with symbols underneath them. There are also doors with two symbols inscribed on them. You’ll need to pull the knockers that match the symbols on the door looking for skeletons you build the doorway. Use Revelio to see which doors have the skeletons then guide all the bones to the doorway. Once it opens, head through and follow the hallway to the next room.
As you head across the room, you’ll be jumped by a group of spiders. Take care of them then burn the web on the east side of the room. Head over to the table and collect the two scrolls there. Speak with Sebastian afterwards regarding the relic. Either option doesn’t matter as he will grab it regardless. Exit the room to run into Ominis. Speak with him and he’ll ask you to help convince Sebastian to leave the relic. If you agree with him, this will persuade Ominis to allow Sebastian to leave with the relic. To leave the dungeon, make your way back to the room with the alter.
Once outside, head to Feldcroft. When you get there, it will be under attack by Ranrok’s forces. Defeat them all to witness a cutscene. You’ll then need to speak with Solomon to complete the quest.
In the Shadow of Distance
This quest becomes available immediately after completing the previous one. Travel to the Undercroft near the Defense Against the Dark Arts Classroom Floo Flame in the Astronomy Wing then speak with Sebastian. This will complete the quest.
In the Shadow of Hope
The quest will become available during the Prepare for Your O.W.L.S. main objective after some time passes. Travel to the Feldcroft Floo Flame then head east just outside of town to find Sebastian and Anne. Speak with Sebastian to complete the quest.
In the Shadow of the Relic
You’ll obtain this quest after pushing forward in the story a bit after completing the previous quest via an owl from Ominis. Make your way to the Feldcroft Catacomb Floo Flame in the Feldcroft Region and speak with Ominis there. Head into the catacomb then make your way toward the chamber where you found the relic. After fighting off two big ground of Inferni, speak to Ominis again.
Press on heading east through the catacomb to find Sebastian. You’ll need to create a skeleton bridge using bones from their crypts. Head up the stairs and speak with the man of the hour. This will lead to a boss fight with Solomon who has three sections of health. Defeat him to trigger a cutscene.
Afterward, follow Sebastian out of the catacomb and speak with him outside. This is your chance to learn Avada Kedavra. You’ll be prompted with two choices: “No one should know that curse” and “Everyone should know that curse”. Choosing the first one means Sebastian will not teach you the curse. If you choose the second one, you’ll need to follow it up with “Yes please”. Sebastian will then show you the spell sign.
No matter your choice, the quest will complete when the conversation is done.
In the Shadow of Fate
Sebastian will reach out when he’s ready to talk. Travel to the Undercroft to speak with him. After that, speak to Ominis. You’ll have to choose whether to turn Sebastian in or not. Make your choice to complete the quest.
In the Shadow of Friendship
After some time passes from the previous quest, Ominis will send you an owl. Travel to the Undercroft to find him there and speak with him. This will complete the quest and Sebastian’s relationship questline. Please note, this was after turning him in.