In just a week after declaring their alliance with Lucius and the Daitans, Japan faced various types of sanctions from the world. They ignored demands for Lucius to be handed over, and a few countries even threatened war.
Thankfully, the people of Japan had complete trust in Emperor Hidetaka, so they never questioned his decision. In their opinion, this man was akin to a God, and if he decides Lucius is the right option, then he must have good reasons for that.
Also, Lucius's display of overwhelming strength and respect by returning Krv's corpse in one piece attracted the respect of Daitans which was shown to humans.
The friction between both forces died out and they quickly learned how to get along.
Emperor Hidetaka and Nixara both had to keep their troops prepared as they sensed war was coming soon, giving Lucius the chance he needed to rest and recover.