Warning: Spoilers are unmarked.
- Katya was adopted by the Stone Princess, why, exactly? She was, according to the mirror, kidnapped by the Princess to become her servant. However, the Princess hardly takes any interest in raising her, and had she wanted an obedient servant, she could have just kept Katya brainwashed (she is able to do so!). Maybe Katya's job is to lure potential masters to the Book of Masters and persuade them to work on Alatyr? But the last master was around when she was a toddler, and previously they had popped up only once a century. If the Princess hadn't given Katya an extended lifespan, why, again, did she bother kidnapping the girl? Ivan does appear sooner than expected, but only thanks to a string of lucky coincidences he isn't killed by Baba Yaga before the Princess even learns about him.
- Why did the Princess make Yangul look like a human, as opposed to the rest of the ardars? Of course, it makes perfect sense out-of-universe, because for the viewers, a granite golem would have been a lot harder to sympathize with than a good-looking young man (not to mention that the Heroic Sacrifice would have been underwhelming, since the ardars look like stone already). But why did the Princess need that? If she wanted to be able to distinguish the ardar commander from the rest of the army, there were many other ways to do it (helm or armor of a different color, for example).
- There is a fan theory that Yangul Was Once a Man. Which does make sense: say, the Princess realized the ardars' stone brains were no good with strategy and decided to find a human to command them. Which makes it a colossal case of They Wasted a Perfectly Good Character. Was Yangul kidnapped as a baby and given a stone heart? (This possibility raises the question of why on earth the Princess couldn't do the same with Katya). Or did he make a deal with the Princess (something like "the human heart in exchange for immortality, invulnerability and battle skills"), much like Peter in Wilhelm Hauff's The Cold Heart? Then it is an even worse case of wasting a character, because exploring that backstory along with his ultimate Heel–Face Turn would have been fascinating.
