For all those lost about the factions and characters, I'll post my (updated!) summary from the last chapter (I know I needed one too, sigh):
Fonclanc: The country Yuusuke is working for right now. Ruled by king Esvobus, father of Violet, the twin-tailed princess. Divine artists are the elite, but things aren't as bad for the powerless as in other countries. Most of the cast are from Fonclanc, including Sun, the entire Dark God Squad, Kreivol (the princess' assistant), Hivodir (a fiancé candidate for the princess) and old master Zeshald.
Gazetta: The only country where the powerless rule. Shinha, the big white-haired guy, is their king. The loli grandma, Ayuukas, is also from there. They've proven their power after conquering Nossentes, but that expansion is making Fonclanc and Trentrietta uncomfortable.
Blue Garden: A neighbouring country ruled by divine artists. Thanks to Yuusuke's intervention, queen Rishaleus (who was also Shinha's childhood friend) now rules it without being a puppet of a rather warmongering faction. Reifold, the shady spy, seems to be from Blue Garden... but he also seems to be working for several factions at the same time.
Nossentes: Another artist-ruled country, their Divine Council tried to use song princesses like Lasanaasha and Laazasshia to manipulate and get rid of Yuusuke. They also used other agents to cause trouble to their neighbours. In the end, they were destroyed by Gazetta and there was much rejoicing.
Trentrietta: The last country Yuusuke has visited. They're said to be hedonists and pacifists, but House Elfodras wants to change this. They were the ones behind the monster facility and seem to plan a rebellion as the "Wind Blade". Reie, the girl, is the current head of the house after her father died, but the actual power in the family is in the hands of general affairs chief Fotres, finance chief Ailzahha and military chief Benefost.
From what I understand in this chapter, Fotres and Ailzahha are planning to ger rid of Reie to galvanize their forces and, with their monsters and mercenaries, start an uprising against Trentrietta's government. Knowing that Fonclanc and Trentrietta are at odds with Gazetta, they reached out to king Shinha to cause some trouble in the frontier so that Trentrietta's army is distracted.
Meanwhile, Yuusuke is busy with his inventions. But he's going to be in trouble, because after his many victories there are rumors being spread that whoever earns his favor will get lots of good things. In Fonclanc, people think it's all about position and amazing gifts (it doesn't help that his Dark God Squad is getting promotions and cool uniforms, and his inventions are truly amazing), whereas people outside the country believe he will lead entire countries to victory. That's why Reie was told that "World Hegemon" nonsense and is currently going to meet him.