They’re much simpler than they seem
Hogwarts Legacy has a selection of activities and tasks that will be prevalent throughout the entire experience. Merlin Trials are a big one, as they’re quietly introduced through the main story, but open up across the entire world map: to the point where it’s going to be one of the last things you’ll do for your platinum trophy.
But there are also a few puzzle concepts that are only used a few times: then are never heard from again. That includes the Slytherin Locks. Although you’ll only see them sparingly, here’s how to solve them and get them open.
Match up the symbols on the gates to the symbols on the snake
When exploring the tomb in The Shadow of the Study quest with Sebastian and Ominis, you’ll come across peculiar looking snake contraptions. As you might imagine, these are Slytherin Locks. Their solution lies within the gates scattered across the area. The simple way to approach Slytherin Locks: just match up the symbols on the lock (top and bottom) with the symbols on the gates.
As you can see in the image above, the top symbol is a fish-like icon. That’s the top symbol you’ll need to display/rotate to get for the Slytherin Lock. Repeat the process for the bottom lock (and other similar locks/gates) and you’re done!
How to complete In the Shadow of the Study quest
You’ll initially start the In the Shadow of the Study quest after completing In the Shadow of the Bloodline and waiting a full day. Sebastian will ask you to meet him outside the Slytherin Common Room, where he’ll mention the Dark Arts and Ominis’ family’s involvement with them. You’ll both talk about a Scriptorium, prompting you to light three braziers in quick succession to open its doorway.
Upon entering the Scriptorium, you’ll use Reparo to help Ominis open the first entrance before being introduced to the Slytherin locks and gates. Each gate has a pair of symbols, which you’ll have to remember and match using the locks. Since the rooms are dark, you can light the nearby torches using Incendio or Confringo to make it easier to see the symbols.
As you solve each lock, you’ll unlock the area’s gates, allowing you to progress further and reach the final door. Here, you’ll learn about the Cruciatus Curse, giving you three options for the situation. The choice you pick depends entirely on whether you wish to learn the curse and who suffers from it.
Regardless of your pick, you’ll open the door to the Scriptorium. Pick up Slytherin’s Spellbook and give it to Sebastian before leaving the area. Now, at last, you’ll head back to the Slytherin Dungeon, wrapping up the In the Shadow of the Study quest in Hogwarts Legacy.