Stendahl builds an entire mansion just to kill the people who burned his library. Seriously. Now, we know that Ray Bradbury takes book burning pretty seriously, but—whew. That is some revenge, right there.
Of course, it helps that Stendahl is rich, patient, and a careful planner with a rich appreciation for fantasy. It's interesting that he's both a good planner and a fan of fantasy—proof that fantasy doesn't make one incapable of living a full and practical life. (Although apparently it does make you murderous, so there's that.)
He plans the house down to the last detail, and when it's finished, he practically rubs his hands in glee. He "drank it in, the dreariness, the oppression, the fetid vapors, the whole 'atmosphere,' so delicately contrived and fitted."
Sounds like a great place to visit, right?
See, when the book burners on Earth destroyed his books, Stendahl was rich and patient enough to plan a ridiculously complicated revenge. Not only does he have this entire house built to his specifications—drawn from Poe's "The Fall of the House of Usher"—but he befriends a lot of people he wants to kill so they'll come to a party at his house.
(It can be so hard to get people to come to a party, especially when you're planning on using robots to murder them all.)
We'll give Stendahl this: it's pretty cool the way he kills his victims in ways that reference books that they've burned but not understood. On the other hand, those "reading is fundamental" posters in the library convey a similar message with less carnage.
Oh, and quick brain snack: "Stendhal" (note the slightly different spelling) is also the pen-name of a French author Henri Beyle (1742-1842), which connects this character to the long history of literature. His satirical writing took aim at the hypocrisy of the French aristocracy and one book, The Red and the Black, even prophesied a popular uprising. Sound shocking? It was. In 1964, Brazil's new government ordered "subversive" books to be burned. The Red and the Black was one such book.
Stendahl's partner in crime, Pikes, has his own vendetta. He's a former actor and now special effects guy, and a lot of his movies were burned in this big purge that happened on Earth. We're thinking Hayes Production Code here; until 1968, all movies produced in Hollywood were subject to pretty strict guidelines about what they could show.
Pikes seemingly used to be a great actor. Stendahl compares him favorably to famous horror movie actors like Lon Chaney, Boris Karloff, and Bela Lugosi. (See "Shout Outs" for more on that.) Pikes's job in this plan is building the robots and making them look like the original people. So maybe he also does makeup and special effects.
Whatever Pikes used to be, now he's dedicated to revenge. He's not a particularly interesting character, since the story mostly focuses on Stendahl.