I've come to the conclusion he's ENTj.

* he mocks people for their idiocy, insinuating that their is poor
* he is obsessed with power and the attainment of it
* he seems to find the concept of a soul foreign, suggesting weak
* he has a role as a creator of bad feelings in people, a purpose explicitly given to him
* he is plagued by health problems, and is frightened by the sight of his own blood. Both of these are indicative of weak .
* He is mentioned as being quite a talker by Queen Hilda, always coming up with elaborate plans

And Garland... I believe he's an INTj, very much like myself.