@Ayaka I have a feeling that that had always been is intention and the reason he went after the Axis. Planche learned Callian was assassinated by Brisen to place him on the throne as a puppet king while Brisen ruled behind the curtains, so Planche went after the Axis to turn back time, save Callian and do whatever it takes to put him on the throne. That's my personal theory, so take it with a grain of salt.