One month passed on a whim. None of the trio was able to even keep track of time because they were completely focused on getting ready for the D-Day.
The intensity and the sheer dedication that Kaya and Eva had to put into it was incomprehensible. They even shattered Kai's predictions of how things will move. He was impressed at how talented the two were.
At first, he thought that with his plan, they would barely be able to finish before the Red Rose Day. But, when he saw the rapidity of their improvement, he completely changed his plan route. Even after spending a long time with the two of them, he apparently failed to realize how monstrously talented the two girls were.
It was of course good news for him as the stronger they became, the less he had to worry about something bad happening to them. Kai is strong, but he can't be everywhere, every time, all at once. Especially during this mission, they were bound to separate and fight their own fights.
(The rankings in divinity are: Ascenders, Archangels, Virtues, Ophanims, Seraphim. The rankings depend on the power level which will be further explained later. For now, that should be sufficent.)