The following contains spoilers for Lucifer and the Biscuit Hammer Episode 4, "Asahina Hisame and Shinonome Hangetsu," now streaming on Crunchyroll.
Humans are complicated creatures. Growth in one area does not always equate to overall progress into a better human. In Episode 4 of Lucifer and the Biscuit Hammer, Lizard Knight Yuuhi Amamiya provides a stark example of this. After facing his trauma head-on and returning a more stable person, Yuuhi showed some of his most sinister qualities by analyzing his temporary ally, Dog Knight Hangetsu Shinonome. Can this new comrade serve as the beacon to turn Yuuhi away from the darkness, or will Yuuhi's devotion to Samidare's aims lead him to destroy the planet and everyone who stands in their way?
After returning from his hometown, Yuuhi and Samidare were surprised by the appearance of the second of the Beast Knights, Hangetsu Shinonome. Even with Samidare's immense power as the Princess and Yuuhi's newfound confidence, Shinonome continued to best the pair in every sparring match. Nevertheless, he remained completely unaware that the two were anything other than friends in the battle to stop the Biscuit Hammer, blissfully envisioning them all as heroes of justice.
Shinonome seemed to take a particular notice of Yuuhi, offering to train him to get stronger. This is surprising, seeing as Yuuhi resorted to taking Shinonome's partner Ludo hostage when Shinonome was testing Samidare's capabilities. However, it may be Yuuhi's willingness to use such underhanded tactics that made Shinonome realize the younger Knight needed someone to show him the way.
Despite Shinonome's enigmatic debut and impressive skills, he showed himself to be more carefree than Samidare. In stark contrast to his martial prowess and ability to even defeat a Golem by himself, Shinonome appears to have a blissfully lackadaisical personality. In addition to taking naps on park benches and introducing himself like a tokusatsu fighter, he is also the type that swiftly falls in love, swooning over Samidare's sister Hisame.
Though it played itself as a joke, Shinonome's interest in Hisame served as a driving element of Lucifer and the Biscuit Hammer Episode 4. It brought him to Yuuhi's university -- where Hisame is a professor -- and teased a secret about his brother Mikazuki, another student at the college who is missing in action. Yuuhi took note of the strength of Shinonome's crush as well -- not to root them on, but to find a possible weakness in Shinonome's defenses.
Seeing Shinonome as a threat to Samidare's plan to end the world after stopping the Biscuit Hammer, Yuuhi shows little hesitance in plotting his supposed teammate's downfall. Though it is unclear how serious he is, Yuuhi even mulls over the idea of kidnapping Hisame for a chance to kill Shinonome. This is because he knows that while Shinonome will be a tremendous asset in fighting the Mage and the Golems, he may also be the biggest obstacle to Samidare's ultimate goal.
While Yuuhi may have taken the moral high ground with his grandfather, these thoughts demonstrate that he has not yet given up his hatred of humanity. Confronting his counterpart for this treachery, Noi compared Yuuhi to a child throwing a tantrum, breaking his toys because they don't suit him. Still, this chastisement had little impact on Yuuhi, whose internal image is too self-deprecating to care about such things.
Yet Shinonome may be the key to bringing Yuuhi over to the side of heroism. Aside from getting involved in their supernatural affairs, Shinonome also imposed himself on Yuuhi and Samidare's mundane lives. By dragging Yuuhi out to drink with Hisame, talking about romantic pursuits and watching magical girl anime with him in his apartment, Shinonome forced Yuuhi to come out of his self-isolation. In contrast to Samidare, who gave Yuuhi a master to serve, Shinonome has given him a potential friend to live for.
This extends to their aims as Knights too, as Shinonome clearly has much to teach Yuuhi about fighting and their powers. But most importantly, he may be Yuuhi's first impression at someone to look up to. Samidare honed into this quality as well, comparing Shinonome to her visiting father, calling them both "adults who show kids that it's fun to be a grown up."
As it stands, Shinonome seems on track to be a reliable member in the war to stop the Biscuit Hammer. At the same time, if Yuuhi and Samidare continue with their scheme to annihilate Earth, the two may come eventually come into a conflict with him that can only be resolved with blood. Hopefully Shinonome can bring about a change in both Yuuhi and Samidare as Lucifer and the Biscuit Hammer continues.