You and Ango are close apprentices. You both work really well together. Recently, you encountered a problem, that problem being the Decay of Angels. You both couldn't really counter them, you needed information. But you had a clever way of obtaining that information...

You became a member of the Decay of Angels, while secretly relaying all important information back to Ango... Simple enough... Whenever you obtained important information such as future plans or major weaknesses of the Decay of Angels, you delivered it back to Ango.