With the help of traitorous nobles, Nero has removed his father Milliard from the throne and has become the "Holy King". The country is now full pro-Church, and is renamed "Neo Avalon".
Avalon allies with Daidalos against Spada. Spada allies with Pandemonium (Kurono's country), who sends reinforcements.
While Kurono is waiting at the border with Avalon to intercept Nero and his army, the King of Spada is waiting at Galahad Fortress to intercept 100000+ enemy troops from Daidalos...
The latest chapter ends with bad news: the Church has captured Galahad Fortress...
--------------------------------
I assume the enemies are also scheming to rescue Apostle Ai, who is held captive in Spada...
Anyway, the new arc name can be interpreted as "The Day Spada Fell"...
If Spada is defeated, maybe this will finally convince Kurono to become Maou, and take the reins of Calamara/Pandemonium...