WARNING: The following contains spoilers for Episode 17 of How a Realist Hero Rebuilt the Kingdom, streaming on Funimation.
How a Realist Hero Rebuilt the Kingdom is an isekai about Souma Kazuya, king of the fantasy kingdom of Elfrieden. Souma's reign has been dominated by a civil war and a war with the Principality of Amidonia, the effects of which are still felt within the kingdom. Episode 17 saw Souma deal with one of the conflict's most ironic casualties as he visited the arrested Duke Georg Carmine in his dungeon cell.
During the civil war, Duke Carmine harbored various corrupt nobles while under the pretense of standing against Souma's plan to unite the kingdom's three armies. Instead, Carmine betrayed the nobles and had them arrested as soon as he got them all into one room. The Elfrieden public still recognized Carmine as a traitor to the kingdom, and this was a secret Souma wanted to keep -- even if it meant executing the former duke. Souma knew he couldn't easily reveal Carmine's plan publicly in order to let him go free. As Carmine pointed out, the families of the soldiers who died in the battle between his and Souma’s forces would be outraged to learn they were essentially working together.
Souma soon revealed the nobles in question had been executed, discussing the disturbing legal requirement that those related to the nobles within three degrees must also be executed. Carmine asked if it pained Souma to take the lives of others, to which he incredulously replied, "There's no way it could be easy on me!" It is shocking to see the usually diplomatic Souma so angry. The contrast was only highlighted by Carmine's stoic acceptance of his fate, which seemed to aggravate Souma even further.
Although he understood the reasoning behind potential accomplices being executed, Souma still scrambled with Prime Minister Hakuya Kwonmin to get the law reduced to just two degrees. Did he wish he could have done more, or does he simply believe two degrees is acceptable? Souma exasperatedly complained about the ease with which so many could die at his command, so perhaps the Realist Hero protagonist ideally wouldn't execute anyone at all.
If Souma was so reluctant to kill, however, why didn't he use his influence as king to let the nobles live as prisoners? The fact that he and Hakuya struggled just to make the law less severe in time suggests that overturning the death penalty altogether was not an option. Souma likely didn't want to break the current law because that would undermine his authority to exercise it in the future. Bending the law to protect the criminals -- even for strictly humanitarian purposes -- may have caused Elfrieden citizens to accuse him of being just as corrupt as them.
Souma ultimately resolved to execute Carmine as well, even though Princess Liscia saw him as a father figure. Souma lamented hurting Liscia given how loyally she'd served him, and his anger was renewed that Carmine chose this plan knowing he wouldn't survive it. This even led him to become uncharacteristically irrational and desperate; Souma begged Carmine if this was really the only way, despite it already being too late to matter. Even so, his realistic, pragmatic personality still prevailed as he asked Carmine, "Do you know how hard a blow it is to lose valuable personnel?!"
Perhaps Souma was using his emphasis on practicality to mask his actual feelings, or perhaps he didn't respect Carmine as much as he seemed to. And even though the brutally cruel nobles were a serious problem that needed to be addressed, Souma may have been frustrated with the backstabbing nature of Carmine's plan that left him no choice but to execute them. Souma also lamented that many more relatives could have been spared if more conspirators had "cut all ties" with the nobles like Carmine did, and a slower approach to the issue might have given them the chance to do so.
Even so, Souma told Carmine he couldn't stand to see him publicly executed, giving him a bottle of poisoned wine. Carmine immediately imbibed the toxin and fell unceremoniously to his death. Souma then reported the news to Liscia in a similarly brief manner, simply telling her that "Georg is dead."
Liscia may have under-reacted, but the way her quill seemed to instinctively stop in her hands betrayed the effect the news had on her. It's understandable that Liscia may have wanted to maintain a professional demeanor in front of the king, but future episodes of Realist Hero could explore how his death might affect her emotionally.
Souma's final confrontation with Carmine may have been Realist Hero's toughest scene yet, compounded by uncharacteristic fury and Liscia's subdued reaction to her old friend's death. Not even a funny scene later in the episode -- concerning a series of awkward marriage proposals -- could overcome the dark tone of the fateful meeting in the dungeon. Souma is familiar with difficult leadership decisions, but allowing the execution of an intelligent and relatively well-meaning asset to protect state secrets may have been his most painful one yet.