What type of texture is this

Can anyone tell me what this is? I thought it was a normal map, but when I apply it in blender it just makes my texture's dark, even running it through a normal map node. I got it from a a program called ninja ripper from the game path of exile. As far as I can tell my normal faces are right, but I am new to this.

TThe file is exported as a .dds from ninja ripper.