Zuko, the Knife, and Sibling Relationships in "Zuko Alone"
Zuko Alone is an episode with two different plots, one in the present and one in the past. Both plots are largely about Zuko's sibling relationships, and Zuko's knife is is a common thread through both, suggesting certain hidden parallels. In particular, the knife, and the parallels we notice if we pay close attention to it, suggest something about what Zuko's wants out of a sibling relationship.
The object of our focus
We should first briefly summarize the role the knife plays in the narratives.
Present Plot:
Lee (the little kid) sees Zuko "stand up" to the bully soldiers, "adopts" Zuko and brings him home, and projects Lee's relationship with his older brother Sensu onto Zuko. For Lee, Zuko is "an older brother."
While Zuko is sleeping, Lee steals Zuko's swords from him and plays around with them, but is holding them wrong.
Zuko finds Lee and shows him how to correctly use the swords.
Lee's father Gansu has to leave for the front, as Sensu has been captured. Zuko gives Lee his knife.
Lee challenges the soldiers with his knife, and gets imprisoned and "conscripted" for it. The soldiers take Lee's knife. Sela, Lee's mother, begs Zuko for help.
Zuko defeats the soldiers and retrieves the knife, but in doing so reveals his true identity.
Zuko tries to return the knife to Lee, but Lee rejects it.
Past Plot:
Iroh gives Zuko the knife and Azula the doll. Azula is clearly jealous of Zuko's gift and burns the doll.
Zuko is playing with the knife. Azula, still clearly jealous, criticizes Zuko's ability with it. Zuko threatens to throw the knife at her head. Azula breaks the news of Iroh's retreat to Zuko..
Azula sneaks into Zuko's room and steals the knife. Zuko finds her playing with it and angerily demands it back. Azula taunts him about it but ultimately lets him steal it back. Apparently, after that, she didn't continue to covet the knife, as it's still in Zuko's possession in canon.
As you can see, there are strong parallels between these two stories. The knife (and to some degree it's equivalent, Zuko's swords) function as a source of discord and conflict. Most of the conflict between Zuko and Azula (not all of it) in this episode is actually about the knife. In particular, we can identify a series of parallels:
The knife as a gift, passed down from someone older and "wiser." Iroh passes down the knife to Zuko and Zuko passes it down to Lee.
The swords/the knife as an object of desire, something stolen. Azula steals the knife, while Lee steals Zuko's swords, another bladed weapon.
Playing with the knife/the swords. Lee, Zuko, and Azula all do this.
The knife as a source of trouble and discord. Much of the conflict between the siblings stems from Azula's desire for the knife. Meanwhile, Lee gets the knife and immediately proceeds to use it to get into hot water.
We also can see some parallels between Azula and Lee in particular:
Lee sees Zuko as an older brother, while Zuko is Azula's older brother.
Young Azula and Lee are about the same age.
Both Lee and Azula are troublemakers: Azula throws fire at an apple on Mai's head, while Lee throws eggs at the soldiers and later threatens them with his knife.
Azula and Lee both say uncomfortable things and ask uncomfortable questions. Lee is the only person within the entire series to ask Zuko how he got his scar, for instance.
Both Lee and Azula ultimately reject the knife. Lee refuses it and Azula allows Zuko to retrieve it.
If we accept that Lee and Azula are parallel characters (not the only possible reading of the episode, but a compelling), the question that remains is why their relationship with their "older brother" Zuko so different? How and why is Zuko's behavior so different?
When Lee steals Zuko's swords, Zuko responds positively and kindly to it, and he eventually gives Lee his knife. We can almost see this as a "do-ever" of what happened with Azula. Azula was so clearly jealous of Zuko getting a knife, and so desperate for it. Zuko could have offered to share the knife with her, or even could voluntarily gifted it to her. I am not demonizing young Zuko for not doing so. He was a kid, and it's not like Azula was being particularly nice to him even before that. Yet if he had, most of the conflict between Zuko and Azula in that episode would have been defused, and the consequences would have potentially reverberated up to the present.
Perhaps we can see Zuko's treatment of Lee mostly as a do-over, as Zuko, unconsciously, making different and better decisions in a similar situation now that he's older and (perhaps?) wise. Or perhaps there is yet another piece of this puzzle. There's something true about Lee that isn't true about Azula:
Lee: I think you'd really like my brother Sensu. He used to show me stuff like this all the time.
Lee looks about Zuko and adores him, and Zuko can in turn teach Lee stuff. Perhaps this is why Zuko ultimately responds so positively to Lee. At some level, this is the sort of relationship Zuko wants to have with a younger sibling.
On the other hand, Azula will never look up to Zuko, will never adore him. She could love him with her whole heart, be the nicest sister in the world to him (which she never is in canon, be clear), even try to hand him everything he ever wanted, but she'll never look up to him. It's simply not in her nature. He'll never be able to teach or show her anything. Zuko can't have the sort of relationship he has with Lee with her.
The Zuko-Azula sibling relationship is dysfunctional for many, many reasons,* but this another reason why it is so, one that I've never seen any recognize.
*Abuse, sibling competition, generationally terrible parenting, toxic imperialist culture, toxic masculinity, Azula's sharp tongue, bad luck, etc.
