WARNING: The following contains spoilers for Episode 19 of How a Realist Hero Rebuilt the Kingdom, now streaming on Funimation.
Episodes 17 and 18 of the fantasy isekai How a Realist Hero Rebuilt the Kingdom were especially dark, as the kingdom of Elfrieden's modern-day king Souma Kazuya executed multiple enemies of the state. Episode 19 advances the plot and presents Souma with significant national challenges, but also provides some well-timed comic relief and an exciting new character.
It began with knight Ludwin Arcs alerting Souma that an acquaintance of his had done "something outrageous." Given Souma's brutal response to those who could potentially subvert the kingdom in the future, it's unsurprising that Ludwin would report his friend rather than risk being accused of collusion. Along with Princess Liscia, they traveled to a clearing in the woods to investigate the person in question. Souma would meet an unexpectedly familiar sight that challenges what he thought he knew about Elfrieden -- and the magical world that surrounds it.
Souma was shocked to find what appeared to be a modern-day garage. Ludwin explained it was the entrance to an abandoned dungeon that had been converted into laboratories. Just as Souma was getting used to understanding Elfrieden's rules, it must have been galling for his progress to be challenged by the sudden appearance of a mundane utility from his world. The incongruously modern entrance foreshadowed the forward-thinking nature of its inhabitant, who let them in via the use of a lo-tech pipe-based equivalent of an intercom system.
Liscia, who was unsurprised by the glowing metal corridor within, nonchalantly explained that she assumed it was magic, which settled the issue in Souma's mind. His own surprise potentially mirrors the audience's. It is as if he had mentally classified Liscia and Ludwin as existing in the fantasy genre, and the glowing metallic dungeon as sci-fi -- even though both exist in his reality. Souma's disbelief at the futuristic scene -- in contrast with the characters who actually stood out more but didn't care -- was an amusing twist on the genre and its expectations.
Inside, Ludwin chastised the scientist who worked there, Genia Maxwell, for not recognizing her royal company -- which she overcorrects with a curtsy and exaggerated politeness before returning to casual speech. Souma, who has a consistent demand for talented people and a disregard for formality, was drawn to Genia. This appreciation was recognized by Liscia, who frowned in apparent jealousy. The three soon forgot the purpose of their visit and discussed technology, such as communication gemstones.
According to Souma, it's widely assumed in Elfrieden that Sylph and Undine spirits power the gemstones, but Genia revealed this is not necessarily true. They discussed how people often provide spiritual explanations to help understand things. In a world where magic is undeniably real, it might have been oddly refreshing for the logical, analytical Souma to debate mythological uncertainties. The fact he has the privilege of knowing about modern history and politics does not make him the only free-thinking person in the kingdom, and Genia was also relieved to meet someone who appreciated her skepticism.
Genia introduced her visitors to a new invention: a giant hoop-shaped engine that could launch airships. In Episode 19's sole action sequence, Ludwin had to deactivate the device after it produced a blast of air that threatened to blow all four away. Seeing the knightly figure press a red button with his gauntlet encapsulated the juxtaposition between fantasy and science that made this episode so unexpected. Genia likewise got to revel in some genre-typical mad scientist absentmindedness, confessing with a smile that she had accidentally positioned the device the wrong way round.
The scientist then revealed the machine's power source: a rock known as "curse ore," so named because it explodes when mined with magic and a significant vein of it runs underneath Elfrieden. Genia decided to use it as a power source when she wondered where its explosive energy came from. Souma realized she had discovered a mineral that could store energy, similar to fossils in real life.
Despite the potential of Genia's discovery, Souma's more cynical, realistic side provided an important reminder. Elfrieden’s plentiful “curse” being a valuable resource could draw conflict if other nations learn how to harness it. Knowledge of real life wars for resources gives Souma an insight more likely for an isekai protagonist from another world to have. This is an example of how Realist Hero takes advantage of its genre, justifying why it needed more than a straightforward fantasy premise.
Souma ultimately decided to find someone for Genia to marry in Elfrieden to keep her groundbreaking ideas within the kingdom, unknowingly also resolving Liscia's jealousy. Even so, Souma maintained a relatively modern approach to political marriage. He told Genia honestly that her importance to the kingdom motivated the idea, matching her with someone she actually liked: Ludwin. Ludwin then remembered Genia's crime that brought them there to begin with, but her impression is overwhelmingly that of a funny, resourceful scientist who is unlike any other character in Realist Hero.
