One of the Three Founders of the Corporation, Armanstead is the illusive and enigmatic of all the founders. He mostly handles Infrastructure and monitors the operational efficiency of the Corporation, making improvements where he can and otherwise keeping the Corporation a well-oiled machine.
Constantine revealed to Bek and Mac that Armanstead is one of the original 7 Architects that designed and constructed the God Machine a long time ago. While the Machine was able to wipe out his 6 brethren, Armanstead survived extermination and has been working ever since to put a stop to his creation that has grown wildly out of his control.
As such, Armanstead is a creature of unknown origin whose powers remain a mystery even to the highest ranking members of the Corporation.