Character Analysis
Guenever is Arthur's queen… and if you know the legends, then you know that she sleeps around with Sir Launcelot and brings the whole kingdom down in the process. Twain doesn't have much use for her here, and she's mainly background noise, flirting with Launcelot and making Arthur miserable in the process.
As with the legends, her infidelity causes Launcelot and Arthur to turn against each other and destroy the kingdom in the process. She reminds us of the specifics of Arthurian literature, letting Twain make fun of it (and tell his own story) while the original drama plays out in the background.