Hogwarts Legacy takes you on a journey through Harry Potter's magical world and Fantastic Beasts. Sebastian Sallow, a fellow student from House Slytherin, becomes your companion during the main and side quests. As Sebastian's quests near the end, you are in a dilemma whether or not to report him after he killed his uncle with a Dark Magic curse.
Should I bring Sebastian into Hogwarts Legacy?
Sebastian and his friend Ominis Gaunt are seen in the Undercroft during the quest For the Shadow of Fate. You have a conversation with Ominis to decide whether or not to bring Sebastian to Hogwarts for his crime. If you do not report Sebastian, you will be expelled from Hogwarts, and you will not be able to see him again.
If you haven't yet learned the Unforgivable Curses, i.e., Crucio, Imperio, and Avada Kedavra, be cautious about making a decision. These curses may be acquired by making the appropriate dialogue choices during the Sebastian quests. However, you may unlock them anytime later if you don't turn Sebastian in.
Sebastian has been turned in and you haven't learned the three Unforgivable Curses in your current playthrough.
Sebastian's Unforgivable Curses: How to Learn them
To get non-acquired curse spells, go to the Undercroft and ask Sebastian to teach them to you, of course if you haven't turned him in. Go to the Undercroft entrance (first image) at the end of the corridor to your right.
For more Hogwarts Legacy content, check out Pro Game Guides. In the meantime, check out our article on Hogwarts Legacy – Do side quests disappear?