These are the events that transpire after everything that happens in Altissia. From the way it sounds, the things only go downhill and Ardyn stops trying to hide his true intentions from them. If Ignis could reach him right now, he'd snap his neck in two.

Thank the Astrals that by the time Noct reaches revealing Ardyn's true name Ignis is done with his tea.

"...how is that possible?" Sorry Noct, you will have to give him proper explanation here.