Here's a quick guide to finding hidden candles!
I know, I spent forever looking for them too. So, here's a little help with some screenshots to guide you.
Spoiler Alert! If you want to find them yourself, stop reading now!
Tormenture is an awesome game, especially if you love hunting for secrets since it's full of them. Some of them are very well hidden I would say, so I don't blame you if you need some help after feeling like you've looked everywhere.
There's a hidden candle for each main area in the game, making 5 in total. Each one unlocks an achievement and is needed for the secret ending.
These are located in a secret entrance you have to look for, usually disguised as fake walls that you can go through, so it's pretty easy to miss them. Once you go in you are transported into a 1st person maze section where you have to find the candle while avoiding enemies. Don't worry about this part since they are pretty simple and you'll eventually find the candle if you wander around for a bit. You can also guide yourself with the floor colors, which change according to the section of this small maze.
In here I'll add the description of what you're looking for along with the pictures of the room and it's map location. Hope this helps.
Mansion Candle
This is relatively the easiest one of the bunch and most likely the first one you'll find. It's located right inside the fireplace in the room with the NPC drinking tea and the passageway to the basement.


Cave Candle
You'll find this one in the room with the purple door, right on top of it. You'll see some small bloodstains marking the secret entrance.


Forest Candle
While walking through the southern section of the forest you'll come upon this room with 2 shrouded enemies that leave a thorns trail. In a small corner on the left wall you can see some of the markings on the ground going through one of the bushes.


Ruins Candle
In one of the long rooms, specifically the one right next to a clock room, you'll find a small gap at the center of the bottom wall. Just go through and you'll find it.


Maze Candle
In the room above the clock at the bottom right corner of the map there's a single piece of the top wall that's different than the rest. Here you'll find the last candle.

