This is really doing my head in. The door that I have a problem with is the one containing the altar in Chaptor 2 (the one with the shadow over the door)

I have read several posts on how to open it to no avail, they are either not clear or go off on a tangent. From what I can gather is that in order to open the door, the prism must be used. How? I've fired the lightning in every direction and it does'nt open. This is the only door left that needs to be opened. I've given Nathaniel his gear back, killed the 3 sisters, spoken to Nickademus, won up to level 5 in the Battle Realm, travelled every option in the picture. Still need to free the Abashi but need to open the door first I think.

Please help me, dont know what else to do, completely stuck. Thanks

You enter the room from downstairs (word Lysan by the painting), then you open the door from the inside with hide in shadows mode on. Then you use the lightning machine to open the other door.

Fire the lightning projector towards the top of the map. Make sure the mirror outside that door is tilted so that it reflects the shot to the left. If you do those two things once you've opened the door to that room, it will open the shadow covered door.

Thanks guys for the reply, especially Vormaerin. No-one ever mentioned tilting the mirror, didnt realise you can do it, worked a treat :)