Emperor Rael took the first step in crushing Prime Minister Edward's trump card by owning it and not backing down. He knew from the very get-go that it was almost impossible for anyone to believe him if he denied the accusations.
This tied back to the pieces of evidence of Rui's scheme and plan that were beginning to be unearthed and resurfacing. It made lots of people very suspicious of the Emperor of Harmony and any attempt to deny the claims would simply be met with more suspicion.
The only way to break past this swamp was to own the accusation and rob them of their strength.
This was an extremely risky strategy, for obvious reasons.
For one, there was a lot of resentment tied to the outcome of the Kandrian Throne War. A single mistake would cause all that resentment to choke the Kandrian Empire and deprive it of all its political support.
That was why he started with Kandria's allies before anybody else.
