In Volume 1, Book 3, Chapter 7, Gawaine's refusal to have mercy on a knight who killed his hounds leads him to accidentally behead the man's lover. This scene, laced with situational irony, foreshadows Gawaine's eventual role in the civil war that destroys the knights of the Round Table:
‘Thou shalt die,’ said Sir Gawain, ‘for slaying of my hounds.’
‘I will make amends,’ said the knight, ‘unto my power.’
Sir Gawain would no mercy have but unlaced his helm to have stricken off his head. Right so came his lady out of a chamber and fell over him, and so he smote off her head by misadventure.
‘Alas,’ said Gaheris, ‘that is foul and shamefully done, that shame shall never from you; also ye should give mercy unto them that ask mercy, for a knight without mercy is without worship.’
Gaheris takes the opportunity to preach to Gawaine about the necessity of mercy in chivalry, but the irony does not solely lie in Gawaine's failure to act like the knight he is supposed to be. On a deeper, more human level, Gawaine is utterly convinced that killing the knight in revenge will right the wrong that has been done. His rigidity in this conclusion makes him unable to react to further information (either the request for mercy or the sudden appearance of the man's lover before his blade). Ironically, his total confidence that he knows how to right the situation causes him to make everything worse. As Gaheris says, "that shame shall never from [him]" (he will never be rid of the shame of what has just happened).
This moment is formative for Gawaine in that afterwards he must commit himself to defending women, but he does not learn from it as much as he ought to. His ill-fated certainty that revenge will right a wrong foreshadows his reaction to his brothers' deaths at Launcelot's hand. Launcelot kills Agravaine, Gareth, and Gaheris not because he wants to, but because he is cornered. In the case of Gareth and Gaheris, he is not even defending himself, but rather Guenever, who has been sentenced to death. He charges in and kills the people he thinks are going to kill her before even realizing that Gareth and Gaheris are among them. When Gawaine learns that Launcelot has killed his brothers, he is again so angry that the only path that he can see is revenge. His need for revenge becomes one of the primary reasons Arthur escalates the fight against Launcelot to the point that they destroy one another. If Gawaine had learned to suppress his appetite for revenge, the knights of the Round Table may never have fallen as they do at the end of the book.
In Volume 1, Book 7, Chapter 11, Linet marvels that Beaumains has continued to put up with her berating remarks the entire time they have been traveling together. Beaumains explains the situational irony:
[T]he more ye said the more ye angered me, and my wrath I wreaked upon them that I had ado withal. And therefore all the missaying that ye missaid me furthered me in my battle, and caused me to think to show and prove myself at the end what I was[...]
Whereas Linet and any reasonable person in this world would expect Beaumains to part ways with Linet or otherwise stop her from being so rude to him, Beaumains explains that her cruelty has actually helped him accomplish his goals. He is trying to "show and prove [himself]," which he is better able to do when he can channel anger at Linet into his fighting tactics with the other men he meets.
Beaumains's interest in proving "what I was" in each of his fights hints that there is more to him than meets the eye. As he reveals several chapters later, he is Arthur's nephew. Linet has already joked that he might have noble blood given his obsession with treating even the rudest women according to the chivalric code. The idea of noble blood carried much weight in the 15th century. Malory seems to imagine that it was an even bigger deal in Arthur's day. A person could become a knight through nobility because chivalry (the code knights were bound by) was supposed to be inherent to noble blood. It was much more difficult to be knighted for simply living up to the chivalric code. Beaumains wants everyone to be able to see, like Linet, that he embodies nobility in his character as well as in his name. He wants to earn the title of knight before anyone uses it for him.
An additional layer of situational irony lies in the fact that it is Linet who first glimpses signs of Beaumains's "noble blood." As his constant detractor, it does not seem that she should be the one to see through to his inherent nobility. This irony further supports Beaumains's notion that Linet is not really his enemy at all. Instead, she is there to help him prove himself to the rest of the world.
An instance of both dramatic irony and situational irony occurs in Volume 1, Book 8, Chapter 24. The queen has given Dame Bragwaine and Gouvernail a love potion for La Beale Isoud to share with King Mark, but La Beale Isoud and Tristram unwittingly share it:
And then anon Sir Tristram took the sea, and La Beale Isoud; and when they were in their cabin, it happed so that they were thirsty, and they saw a little flacket of gold stand by them, and it seemed by the colour and the taste that it was noble wine.
Then Sir Tristram took the flacket in his hand, and said, ‘Madam Isoud, here is the best drink that ever ye drank, that Dame Bragwaine, your maiden, and Gouvernail, my servant, have kept for themself.’
The dramatic irony is the most obvious here. The narrator has just recounted how the queen is planning for the love potion to help La Beale Isoud fall in love with the man she is being sent to marry. The reader knows that the wine Tristram sees must be this very love potion. As Tristram and Isoud prepare to drink the wine, the reader sits in suspense, waiting to see what will happen when the love potion cements not Isoud and Mark's love, but rather Isoud and Tristram's.
The love potion incident is also laden with situational irony. The love potion is the perfect plot device to create an obstacle for a more real love affair. Indeed, that is exactly its intended role: it is supposed to supplant Isoud's love for Tristram so that she will be able to marry Mark without feeling unhappy. Meanwhile, Tristram will be left in the dust. Tristram has promised his uncle that he will bring La Beale Isoud back to Cornwall for Mark to marry. Without knowing anything about a love potion to take the edge off, Tristram is already planning to make this sacrifice in the name of honor. But instead of helping ease the pain of the sacrifice to La Beale Isoud (who doesn't seem to have had any choice in the matter), the love potion instead reinforces the love Tristram and La Beale Isoud already have for one another. The potion that was meant to make the arranged marriage easier instead adds the weight of magic to the main obstacle already in the way.
In Volume 2, Book 17, Chapter 16, Launcelot wakes up after finding the Sangreal and being knocked out for 24 days for trying to get too close to it. There is situational irony in the revelation of where he has been this whole time:
‘Forsooth,’ said he, ‘I am whole of body, thanked be Our Lord; therefore, sirs, for God’s love tell me where I am.’
Then said they all that he was in the Castle of Carbonek.
Therewith came a gentlewoman and brought him a shirt of small linen cloth, but he changed not there, but took the hair to him again. ‘Sir,’ said they, ‘the quest of the Sangrail is achieved now right in you, that never shall ye see of the Sangrail no more than ye have seen.’
The Castle of Carbonek is in Corbin, where King Pelles first showed Launcelot the Sangreal years ago. It is ironic and anticlimactic that Launcelot and all the other knights have spent so much of the book questing after the Sangreal when it was hidden in plain sight all along. This irony serves two purposes in the book. First it highlights the fact that the quest for the Sangreal was always more about the process of finding it than the object itself. The knights are all faced with a series of tests that they pass or fail along the way, and the results of these tests confirm whether or not they are worthy to "achieve" the Sangreal. The story is an allegory for Christian salvation. "Achieving" the Sangreal, as Galahad will soon prove, involves being taken to heaven by angels. In order to achieve this outcome, Galahad proves over and over that he is pure (which, along with some other chivalric components, means that he has resisted all sexual temptation). The earthly location of the Sangreal does not matter because it is first and foremost a passport to heaven.
The other role the irony plays has to do with Malory's ambivalence toward Launcelot as a hero. Launcelot is a great knight, and he is also, often, a fool who can't quite do the right thing. In this case, the fact that he has been chasing after the Sangreal only to end up exactly where he started undercuts the idea that he is a larger-than-life figure. Malory invites readers to laugh a little at Launcelot, but this comical moment also contributes to the image of Launcelot as a tragic figure. As Launcelot learns in this scene, he has come as close to achieving the Sangreal as he ever will. His flaws (his love for Guenever and his difficulty sticking to the "right" path) mean that he is suited to see the Sangreal but never touch it. In this way, Launcelot represents the kind of heroism that is possible after the death of Arthur. Malory laments the way the world has changed since Arthur's days, and the way the rigid principles of chivalry (which Malory portrays as glorious, for the most part) are no longer attainable. Launcelot is tragic because he embodies the person who strives their whole life for the kind of glory Galahad attains, in a world where such glory is simply unattainable.
