The Hunter's Bullet - S1.E16

The Buranki Entei flies freely through the sky... and the one controlling it is not Reoko, but Kaoruko. Demokratia, led by Guy, has used its technology to make Entei recognize Kaoruko as Reoko. Guy then tells Kaoruko that there is a traitor among them in Demokratia, but she's unable to conceal her shock when told that the traitor is a fellow Bubuki user and ordered to eliminate them.