Catch Phrase: Aylward has several, such as "by my hilt!" and "by these ten finger-bones!"
The Consigliere: Lady Mary Loring proves quite capable of managing Twynham Castle in her husband's absence. Especially so when she manages to organize the castle's defenses to fend off a siege by the Socman of Minstead, which ends with his death and his mercenary army fleeing.
The Fellowship Has Ended: The White Company is disbanded in the second-to-last chapter. For good reason, as there are only about 10 survivors remaining out of an original total of 400. That's a 99% death ratio.
Offscreen Moment of Awesome: When Sir Nigel gets captured by the Spanish in the final battle, they sell him as a galley slave. He manages to escape, kills the captain of the ship, and with some help from Samkin Aylward who had been trying to rescue him, they sail the galley back to England with a ton of riches in its hold.
Pirates: Spade-beard and TÍte-noire are Type 1, assaulting the White Company's ship while they are crossing the English Channel.
Rags to Riches: Hordle John eventually finds fortune when he captures and ransoms a Spanish knight. Alleyne as well, once his wicked brother dies, he inherits the Socman's land and holdings.
Rescue Romance: Alleyne first meets Lady Maude Loring when he spirits her away from the Socman of Minstead's harassment. The second time they meet at Twynham Castle, it's pretty obvious they are into each other.
Suddenly Suitable Suitor: Late in the plot, the Socman of Minstead is killed while sieging Twynham Castle, which means Alleyne now owns a sizable estate and a small fortune. It is after he finds this out that he approaches Sir Nigel to ask for his daughter's hand in marriage. Actually a bit better than most examples of this trope, as Nigel would have also required a potential husband to be a man who had proven his courage under fire in addition to being able to support a wife, and Alleyne had definitely proved that in his travels with the White Company.
Suffer The Slings: A group of slingers are part of the Knights of Calatrava & Santiago, the Spanish army that the White Company engages in battle near the end. They are far from harmless, as the slingers kill the archer Johnston as well as over twenty of his men. A bit later, when Alleyne is trying climb down a cliff in order to find help for the White Company, one of these slingers decides to take potshots at him. Alleyne is hit twice, and he suffers shattered ribs and a concussion.
Taking the Veil: Lady Maude makes preparations to join a convent when she receives word that the White Company was wiped out to the last man, including her father and the man she loves. What she didn't know is that Reports of My Death Were Greatly Exaggerated. Alleyne returns to Twynham and takes her away from the convent to marry her.
Wacky Wayside Tribe: Several, particularly the pirates and the peasant uprising. Sir Nigel seems to enjoy these, and is always on the lookout for them. On a more meta level, the real reason why the book reads like a collection of random adventures is because this was originally a serialized publication.