Alternative Character Interpretation: Morgause and her Orkney Clan consider Merlyn to be a "wicked necromancer" for the part he played in Cornwall's death and Uther's subsequent marriage to Igraine.
Angst Dissonance: After a while, Lancelot's angst can start to get really annoying.
Ho Yay: A lot of emphasis is put on how much Lancelot and Arthur "love" each other. In fact, when describing their relationship, the book almost exclusively uses the word love.
Jerkass Woobie: Mordred is an evil murderer and a conniving bastard who plots the downfall of Camelot, but White goes out of his way to show the reader the factors that made him that way, especially his abusive upbringing. Even the worst things he does have an air of tragedy, as he descended into evil due to Morgause and never got a chance to live a life of his own, instead plunging headfirst into revenge. He's heavily implied to have an Oedipus Complex as well, which shows another sign of his massive mental instability. Overall, while Mordred is absolutely evil, the story takes great pains to emphasize that he's just as tragic as any other character.
Romantic Plot Tumor: The relationship between Lancelot and Guinevere in The Ill-Made Knight can annoy some readers, since it takes a story that had previously been about King Arthur and makes it almost entirely about the increasingly-toxic romance between his wife and one of his friends while still asking them to invest in its outcome, and it takes up more of the story of the largest part of the novel than, say, the quest for the Holy Grail or any of the other classic King Arthur adventures.
One of, if not the greatest Tear Jerkers of all literature. The ending, where it all goes down, and it's all so inevitable.
The narration describes Mordred as practically puppeted from beyond the grave by his abusive mother. He never had a choice in life, and while twisted and evil with no attempt to be good or real conscience, it's clear that Mordred is too heavily influenced by his mother's upbringing to be saved, leading to Camelot's downfall. Similarly, after Lancelot's mercy toward him is brought to light before his siblings, Mordred breaks down, screaming that he wished Lancelot had killed him so he didn't seem to be a coward.
Gareth's death. Gawaine and Lancelot begin talking about what he was like, and poor Lancelot not only loved Gareth, but didn't even remember killing him. The worst part is that it's implied Lancelot didn't kill Gareth at all, with Mordred being responsible for the deed, yet he comes to believe he does and it brings the final conflict between Lancelot and Gawaine to its peak.
Tough Act to Follow: Although White wrote many books, none of them were as successful or as popular as The Once and Future King, and with the exception of five (the original edition of The Sword in the Stone, The Book of Merlyn, The Goshawk, Mistress Masham's Repose, and White's English translation of a medieval Bestiary written in Latin), his other works are largely out of print and mostly forgotten.
In his discussion with Arthur and Kay regarding just war, Merlyn provides a defense of imperialism, stating that it is wrong for people to revolt against a conqueror, even if the conqueror is oppressing them. Especially when juxtaposed with his opposition to aggressive war, this defense of empire would not necessarily sit well with modern readers. Indeed it comes off rather hypocritical given that White decided to spend WW2 in neutral Ireland, which was just such a nation.
This version doesn't omit or excuse the detail of the legend that Merlyn helped Uther Pendragon to rape Igraine, resulting in Arthur's birth.
Mordred's conception is portrayed in a particularly disturbing manner, with Arthur's seduction by his half-sister Morgause basically being presented as sexual assault by an older woman towards an inexperienced man, completely averting Double Standard Rape: Female on Male and not in any way being played for laughs. Arthur is treated sympathetically for this and not at all at fault, being taken advantage of. With growing awareness of the effects of sexual assault on men in the 21st century this comes across as a much more positive message.
Similarly, Lancelot being plied with alcohol until he's barely functional and then manipulated into having sex with Elaine isn't really treated as his fault, and his depression and self-loathing afterwards leading him to make other toxic life choices are pretty relatable to other victims of sexual abuse and assault.
The Woobie: Lancelot. He's fundamentally incapable of being comfortable in his own skin, to the point where he spends his entire childhood in the pursuit of becoming the ideal knight, at the cost of such basic skills as tree climbing. He wants nothing more than to be holy enough to perform miracles, but when he actually succeeds, the girl he performed the miracle on rapes him (which is awful enough, but it also means he's no longer a virgin and thus no longer able to do miracles, at least in his mind) and then later traps him in a miserable marriage, which complicates his already complicated relationship with Guenever. The only thing he really has — his status as the greatest knight in the world — is taken from him by his own son, a Child by Rape (his rape), who is basically everything Lancelot wants to be. He's just a heartbreaking character generally.
