External Strategic Deterrent

Emperor Rael had a hard time maintaining his composure when the Gatekeeper reported the fact that Rui stepped in the middle of Operation Clean-Up and displayed his ability to break through the open, causing the birth of two new Masters, one of which went on to massacre all but one Sekigaharan Master.

He didn't know whether to laugh or cry.

On one hand, the secret of the breakthroughs had been revealed.

On the other, Kane had gotten rid of a huge number of Martial Masters, greatly relieving the pressure that the Kandrian Empire would face in Master-level combat.

However, with the intelligence leaked, it was quite questionable whether it was a good idea to let Rui continue battling. He knew that Rui would continue fighting even if he was in grave danger. 

Precisely because he was in grave danger.