Hogwarts Legacy - How To Use Unforgivable Curses And The Consequences Of Using Them

Hogwarts Legacy puts you in the shoes of a fifth-year student at the school, learning magic for the first time. While there are plenty of other spells available, you have the option to learn and use the three Unforgivable Curses; Crucio, Imperio, and Avada Kedavra. Crucio causes someone immense pain, Imperio controls them, and Avada Kedavra kills. These spells are illegal to use in the world of Hogwarts Legacy, but that doesn't mean you can't have them at your disposal if you want to. Here's how to learn the Unforgivable Curses and any potential consequences to using them. Some story spoilers below.

Consequences of Dark Magic

As for the consequences of using Dark Magic, there really aren't any. There is no morality system in Hogwarts Legacy, nor are there choices that lead down different paths. Any NPCs that are with you when you use them might have a shocked reaction and might verbally berate you for using them, but there won't be any gamified punishments.

The curses cannot be used on Hogwarts grounds, reinforced by the game not allowing them to be cast while within the school. As for completing the game in full, the spells aren't required for any Achievements/Trophies, nor will their usage prevent you from unlocking any of them. They are not required for the Achievement/Trophy for learning all spells, nor are they required for completing Sebastian Sallow's questline.

Crucio

You can begin learning the Dark Arts, including the Unforgivable Curses, during the Fall section of the game. These arts are learned as part of Sebastian Sallow's questline, which begins in earnest once you travel to his family home and meet his sister as part of the main story. After this quest is completed, you must speak to Sebastian in the castle after he has an argument with his friend, Ominous. During this conversation, Sebastian will bring up Crucio and talk about attempting to find Slytherin's Scriptorium.

After speaking with him, he will send you an owl starting the side quest "In The Shadow Of The Study," where you will learn the first Unforgivable Curse, Crucio. You, Ominous, and Sebastian all venture into Slytherin's Scriptorium. After solving a few snake dial puzzles, where you need to match symbols on the gates with the symbols on the dial with a time limit, you will be trapped in a hallway where someone must cast the Crucio spell on someone else in order to proceed.

Ominous refuses to cast the spell again and warns that whoever does use it will be forever scarred, worse than the person on the receiving end. Sebastian says that he is pretty sure he knows how to cast it and asks you if you want to learn it and use it on him or have him attempt it on you. There is also a third option, where you can learn the spell, but still have Sebastian do it to you. If you want to learn Crucio, you need to pick one of the two options where you learn the spell. Afterwards, you will find a spellbook and this side quest will be complete.

Imperio

After completing the second trial and advancing to winter, Sebastian will ask you to come speak with him in the Undercroft. He informs you that the spellbook you found contains information about an artifact of some kind that can reverse Dark Magic curses, which could save his sister. After some time passes, he will send you another message.

The next time we speak with Sebastian, it will be part of a main story quest called "In the Shadow of the Mine" where you must meet him at Overlook Mine. However, this isn't where you will learn the next Unforgivable Curse. Around the same time you receive this quest, you will receive another message from Sebastian, saying he believes he has found the relic that could help Anne and has asked you to meet him at a catacomb near Feldcroft.

About halfway through the catacomb Sebastian will suggest teaching you Imperio, which puts the target under the user's control. If you want to learn Imperio, you need to choose the option where Sebastian teaches it to you. Imperio isn't necessary for the completion of this dungeon, so you don't have to use it here, even if you learn it. After finding the relic, Ominous will arrive and yell at Sebastian for his recklessness. After exiting the catacomb, you will head back to Feldcroft, which is under attack by goblins. After defeating them, a cutscene will play where Sebastian uses Imperio to stop a goblin from killing his sister, but his uncle and sister are upset he used Dark Magic. Speaking with Sebastian's uncle will complete this quest and Sebastian will ask you to meet him in the Undercroft, where he says that he will continue researching the relic.

Avada Kedavra

After enough time passes--for me it was shortly after completing the third trial--Sebastian will once again send you a message, asking you to meet him and Anne outside of Feldcroft. This starts the "In the Shadow of Hope" quest. Here you speak with Anne and Sebastian about using the Relic and the aforementioned "Dark Sacrifice," but all that happens here is that Sebastian says he will convince Ominous and Anne to participate and send you another message later.

Before you can continue you will need to have completed the main story quest "Lodgok's Loyalty" before the next part of this questline becomes available. Ominous will message you, asking to meet at the catacombs as Sebastian has become irrational and impatient. This starts the "In the Shadow of the Relic" quest, which is where you can learn Avada Kedavra.

Head back to the catacomb near Feldcroft, where you and Ominous need to head inside and find Sebastian. Head inside to find a ton of Inferni, which are supposedly being controlled by Sebastian. Ominous leaves to run interference with Headmaster Black and after finding Sebastian, his uncle arrives and a fight breaks out. After you defeat his Uncle Solomon, Sebastian casts Avada Kedavra on him. Anne burns all of the Inferni and the spellbook before leaving. Sebastian runs out of the catacomb, where you speak with him again.

When you speak with Sebastian outside, side with him when given dialogue choice. Eventually he will ask if you want to learn Avada Kedavra and you should say you want to learn it. At this point, Sebastian will teach you the killing curse. This does not conclude his questline, but it does mean you now know the three Unforgivable Curses.