Ilyn Toth's Lair in is a secret cellar that you can encounter in the Blighted Village's apothecary. However, you cannot access this secret cellar without completing a few tasks. Ilyn Toth is not a living character, and he is only referred to via his journal, which isn't found that easily.
The cellar, which contains Ilyn Toth's Lair, is behind a counter within the apothecary. However, finding the entrance can be slightly tricky as you need to look for a tiny wooden hatch. If you are unable to find this hatch, the precise location of Ilyn Toth's Lair is X:32 Y:379. Once you locate the secret passage, drop down to the cellar, where you will find a bookcase.
Once you are in the cellar, you will find potions, herbs, and other items that you can loot. You will also find a Doctor's Log; make sure you grab this book, as it will come in handy in the future. There will be a bookcase which you cannot move. Perform an Investigation check on it, and with a successful roll, you will spot scratch marks on the floor. This means the bookcase can be opened. Unless you have a strong companion in your party, you will need to look for a lever that opens the bookcase.
To the left of the bookcase, there will be a stack of boxes that you can throw. Get rid of the box at the very top, which will reveal the lever that opens the bookcase. Use the lever to reveal a secret passage that leads further into the cave.
Once you enter the cave, you will encounter undead enemies you can kill using Cleric attacks if you have a Cleric build in . If you do not have any Cleric abilities, attack them from a distance. Once you get rid of the undead enemies, proceed ahead, and you will see an Ornate Mirror to the east. Interacting with the mirror will result in it asking you a few questions.
Before you answer any of the Ornate Mirror's questions, create a separate save file so you can answer the mirror's questions again in case of failure.
If it isn't apparent yet, Ilyn Toth’s lair is behind this mirror, and
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