What is the Deacon?

Does the Deacon think, what is it exactly and why was there a mural on the wall predicting or warning about it?

Had a thought a while ago that the Deacon itself, since it has a different life-cycle than the Xenomorph, could be way more intelligent than we believe it to be.

Can it talk? what if it can use technology and even fly a derelict ship!

Or could it even be that the Deacon is the female of the engineer life cycle / race?