Of Dairy and Darkness - Novigrad
Location: Gildorf District (Novigrad)
Quest Giver: Purchase Lizard Figurine or discover Aermas' Abandoned Manor
Other Requirements: N/A
This quest can be started one of two ways, by discovering Aeramas' Abandoned Manor or by speaking with the Merchant in the Gildorf portion of Novigrad. If you started this quest by finding the manor then you'll have to visit the Merchant next as he sells a required quest item to progress.
As aforementioned you'll find the Merchant who sells the Lizard Figurine in the Gildorf portion of Novigrad. The location of this merchant is shown on my screen shot below, where I am standing is where he is located. In addition to the Lizard Figurine you can also buy the Jade Figurine from him which is part of The Nobleman Statuette Quest.
With the statue in hand you're not all set to head over to Aermas' Abandoned Manor which is in the far eastern portion of Novigrad (not the town, the area). Here you will want to investigate the entire area as there are some goodies for you to find such as Diagram: Enhanced Feline Armor and notes giving you some more backstory.
Once you're ready to proceed with the quest go inside of the portal here to reach Aermas' Dungeon. The first thing you'll have to do in the dungeon is navigate the maze of cheese. Avoid the poison gas and follow the clear route to the end of the maze. You'll find a crumbled bridge/path that you can jump up on in this area that will lead you to the top of the dungeon.
At the top of the hideout in the room that appears to be a deadend you will want interact with the symbol on the ground to open up a new portal (pictured below).
In the next part of the dungeon you will find some water at the bottom of the stairs and some loot for you to find on the surrounding ledges at the bottom. There will be more loot to find in this part of the dungeon - unlike the previous part. Just keep an eye out.
To right path to proceed through the dungeon is through the under water tunnel to the north, if you get lost just head towards the quest marker. Climb out of the water and follow the ledges until you reach Aermas' Laboratory. You'll battle a Foglet in the same part of the laboratory that you'll loot the Bull Figurine (Quest Item) and use the Eye of Nehaleni to uncover the illusion on the wall - which will lead you to some loot (pictured below).
When you're ready to proceed activate the next portal and go through it. In the next room you'll find a large shield blocking a central podium. On the northern end of the room you'll find a small crystal which you can use Igni on to deactivate the barrier. On the southern end of the room you'll find the same crystal, except you have to use The Eye of Nehaleni to expose it. This one is optional.
Grab the Snake Figurine from the chest and The Emmentaler to complete the quest. Use the Snake Figurine on the white symbol in the back of the room to open up the portal then head on through it.