Red Room Location
The Red Room is the room where you can find the statues of the Beast and the Red Godess, this allows you to view them in the 3D viewer. It also contains comics that will help you to better understand the story of Nimrod.
Note: You need to play in Succubus Mode to be able to access the room
In chapter 3 you start at the snowy area filled with lots of martyrs, all you need to do is walk further into the map until you reach the crossroads where one of those big weird demons are sitting. You can easily kill it when using the heart attack ability. After you killed it look left and go into the tunnel area that leads underground. Once inside kill the Onoskellis, rotate right and press z to activate soul vision. One of the walls will dissapear and allow you to access the secret area. You will walk down the weird meat like stairs and come across a room filled with black hands coming out of the ground, there will be a portrait that you must examine. Once examined go back via the meat like stairs and use soul vision to bypass the wall like before. Then brake the ice wall and follow the path further. When you reach the area with water at your right side swim through that water and continue past the rolling martyrs( don't let them touch you because you will die). Once you pass them turn right and you should see a small crevice that you can slide through and beyond a room with crushing rocks on the walls. Pass the rocks without being squashed ( just go straight) and then from that point turn left. You will see a room with an open doorway similar to the picture you examined earlier. Go inside and you will see the red goddess and the beast golden statues and further on there will be 4-5 comics. That's it you have accessed the red room!