This is the arc of making Hiiro an Highest Rank mercenary, and the revelation of Mimi and Elma's origin.
Of course, Elma is the daughter of the Empire's Count.
Mimi, is a princess, the grand daughter of the Emperor of the Empire. She's the grand daughter of the Emperor's sister who sneak away from the empires castle during their young age for a grand adventure. Elma will notice that Mimi is super looks alike the current princess of the empire, then she contacted the Lineage team of the government to confirm if Mimi's blood is indeed related to the royal family, and boom, she's 100% positive related.
The emperor will meet them personally, then talk to Hiro about his other world being. How did he know? The empires has the logs of the internet, and Hiro is searching for an unknown star system during the Chapter 1.
The emperor i think declared Hiro the highest mercenary rank here.
Then, the emperor will set a contest where other mercenaries will take a chance to combat him to 3 different contest.
I think these are sword fighting, Armor combat, and the space ship battle.
Of course, he won all of that 100% with the help of his other world ability (the isekai skill)