Dragon Age: Inquisition is almost entirely set up in Dragon Age 2 DLC that I don't ever remember actually playing. Not that playing the DLC would have made me give a toss about Corypheus ...
Once I have completed every romance in The Veilguard, I intend to do a complete Dragon Age run sometime next year: Dragon Age: Origins + DLCs (and obviously Awakening), Dragon Age 2 + DLC, Dragon ...