The book is not just based on real events; in some chapters, battle scenes are described with detailed, minute-by-minute accuracy. Also, there’s plenty of profanity in the dialogues—but that, again, is only a precise reproduction of the heroes’ real-life conversations. In the army, you don’t curse with profanity— in the army, you talk with profanity.
The main character is Major Aleksandr Simonov, also known as Shurik—a composite image based on several real-life prototypes. But he’s not the main figure in this book; the main characters are the secondary ones who fight shoulder to shoulder with Shurik. They’re drawn from real soldiers and officers of the Russian army who are—or were— in the zone of the SVO.