Aengus, Aria, and Bella discussed their plans thoroughly and decided to attack Demon Lord Crimson the following day.
Since it was already nighttime, they postponed their assault, keeping the plan a secret from everyone except Aengus' most trusted subordinates.
The delay was mainly because of Bella's insistence of spending the night there.
Targeting Demon Lord Crimson was not a decision made on a whim. Crimson had been the one leading frequent incursions into the human world recently. During the surprise attack on Skyfall City, it was Crimson's army that had been obliterated by Aengus.
Through his meticulous appraisal ability, Aengus traced the origins of those forces back to Crimson.
Their mission was clear: Demon Lord Crimson would be their next target. However, Aengus aimed to conquer Crimson's army with minimal bloodshed, intending to grow the Liberation Army's numbers while avoiding unnecessary losses.