In the Shadow of the Undercroft

In this walkthrough for Hogwarts Legacy, we'll give you the complete tutorial for the main quest: In the Shadow of the Undercroft.

Meet Sebastian at the tower of defense against the forces of evil. He'll ask you to explain your situation. But you need a hidden place to talk freely. Sebastian will show you a Secret Undercroft. 

Follow Sebastian into the secret room. Once inside, explore the room and open the chests. 

Talk to Sebastian. He'll ask you to keep the location of this room hidden and not to share it with anyone. He'll also teach you the Confringo spell, an explosive spell that's forbidden because it can be dangerous. Then practice casting the Confringo spell on the 3 candlesticks hanging from the ceiling. Then go back and talk to Sebastian. 

As you leave the crypt, you encounter Ominis Gaunt, who threatens to keep the crypt's existence a secret. And so the quest: In the Shadow of the Undercroft comes to an end, making way for your next main quest in Hogwarts Legacy: The Map Chamber.