[SPOILER] Plot Discussion Thread *Spoiler Alert*

[frictionalfan]

In this wiki a few interesting articles have been added:

e.g.:
http://amnesia.wikia.com/wiki/The_Machine

The engineer character seems to be the machine which is half of Mandus' soul.

Maybe it isn't a physical body at all which controls the machine; the developers might have just gone with a spiritual approach. That doesn't explain the encapsulated body though, it's obviously a significant person.