Type 3 prophets seem to be a combination of Type 1 and Type 2 as they are able to formulate prophesies as Type 1 prophets do, but they are also experience the compulsion to alter the future as Type 2 prophets do. There has only been one known Type 3 prophet, so using the plural pronoun may be a misnomer, though it is entirely possible that any other Type 3 prophets were significantly less visible than High Mage Mylark . By examining Mylark and through conjecture, scholars have concluded that Type 3 prophets must be mages like Type 1 prophets but are able to act on the prophesies they have; they are in fact compelled to act on the prophesies they give.
If one accepts the hypothesis that Type 2 prophets subconsciously have knowledge of the future which enables them to act, then it would seem logical to put forth the idea that Type 3 prophets bring this subconscious knowledge to consciousness while retaining the ability to act on the future knowledge. This combination makes Type 3 prophets incredibly powerful and incredibly dangerous. Several contemporary historians have written possible alternate histories of what may have happened if Mylark had been working against what philosophers would call the common good.