Should you learn the Unforgivable Curses?

During Sebastian Sallow’s companion strand, he offers to teach the three Unforgivable Curses. You can accept or refuse each one. Learning them does not lock you out of the main ending, and refusing them does not save Sebastian from himself. The curses are tools; the story judges what you do with the friendship, not the spell list.

What changes is the texture of that strand. Accepting puts you deeper in his confidence and gives you the game’s strongest dueling options. Refusing keeps a cleaner conscience and still lets you finish his quests. Either way, the late choice in his story — whether to turn him in or protect him — is the one with weight. The curses are a side door. That decision is the room.