Scrawled notes are obtained by searching the dead mourner near the crystal dispenser in the Temple of Light. It directs players towards using the colour wheel that is obtained alongside the notes and the nearby dispenser to solve the light puzzles during Mourning's End Part II.
We've found the source of the shadows, an ancient temple. This may well be the one we seek. Before heading back to report this, Nissyen has ordered us to have a quick look around. The temple seems to be protected by some sort of light system. Different coloured doors require different coloured lights to open them. I fashioned a crude colour wheel to help us work out which light is needed for each door. We also found a dispenser which contains mirrors that can be used to redirect the light. The shadows are becoming aggressive. We should probably head back.