This ancient key mystifies me… Danos found it in the main chamber, and so far we've been unable to determine its purpose. We've checked everywhere apart from a large hole in the floor – but it’s too dangerous to climb down there.
Still, there’s no reason to try to solve this riddle at this moment. The ruins are dangerous enough without us peeking into every nook and cranny, searching for a treasure that might not even be there.
I will keep the key hidden for now. Maybe one day it shall prove useful.