I can't fully remember that aspect. It definitely wasn't 2D. I want to say it was similar to the style in Now and Then. That 3D is semi-realistic but not hyper realistic. I think I remember when searching the manor/mansion that it becomes a top down 2D style just so you can search the room...
The best details I can remember are that you are a swordsman from potentially another world with a voice of some being in your head that helps you somewhat. Later in the story she is able to manifest in the same world you are in. I remember you having a little group you travel with after saving...
You are on some sort of quest and come across an apothecary who was killed and his daughter kidnapped. You have to find them in the woods and kill the kidnappers. There is also a dark elf or some similar-looking lady who joins your party but is reluctant to trust you.
I can't remember the game...