The Lord of the Rings has plenty of pitiable characters. Gollum might be the best example, as his ill-fated life personified the power of Sauron's One Ring. But there were plenty of other tragic characters. The Nazgûl were promised power and turned into thralls. Similarly, Nerdanel watched her seven sons sail to their deaths, and Denethor slipped into despair after waging mental war with Sauron. However, there's one character that's not even remotely pitiable, and that's Saruman the White.
Saruman was sent to Middle-earth with the goal of rallying people against Sauron. He was powerful and knowledgeable, and he was placed in charge of the White Council. However, Saruman became a traitor. He waged a mental war with Sauron, but rather than contending with the Dark Lord like Denethor did, he gave in and betrayed his mission. That's why Saruman deserved no pity when he was brutally killed. Yet that raises an intriguing question: how was Saruman killed if he was immortal?
Saruman's Death in LOTR's Movies vs. Tolkien's Book
After Saruman gave his allegiance to Sauron, he grew an army of Uruk-hai and set them on Rohan. The Two Towers showed how his army was narrowly defeated and how Treebeard's Ents purged Isengard. With his resources depleted, Saruman shuttered himself in Orthanc, where he stayed until Gandalf came to confront him.
At the beginning of the Return of the King movie, Gandalf, Theoden and company went to Isengard. There, Gandalf removed Saruman's status as an Istari and broke his staff. It was a blow to Saruman's pride and his power, but Gandalf still wanted the best for him. Unfortunately, not everyone did. Gríma Wormtongue stabbed Saruman in the back, causing him to fall from the top of Orthanc and be impaled in a spiked wheel.
That was a terrible death for Saruman, but it wasn't exactly what happened in The Lord of the Rings book. In J. R. R. Tolkien's version, Saruman stayed in Isengard until Gandalf and everyone else left. He then convinced Treebeard to let him out. Upon leaving, he went to the Shire and put the Hobbits under his thrall. When Frodo and the others returned after Sauron's defeat, they had to fight against Saruman's goons. When they won, they confronted Saruman at Bag end, where -- similar to the movie -- Gríma brutally stabbed him,
Why Could Saruman Be Killed - And What Was His Fate?
In both the movie and the book versions, Saruman was killed by a mortal man with a simple knife. But that still begs the question of how he could be killed at all. In order to answer that, one must understand his station on Middle-earth. Like Gandalf he was a Maia, which meant that he was immortal. But, like Gandalf, he was also an Istari. That meant that his immortal spirit was housed in a mortal body. Thus, he could have been killed at any time by anyone.
When Gríma stabbed Saruman, his mortal body was killed, and his spirit fled its dying corpse. If Saruman had been in good standing, his spirit would have gone back to Valinor, where it would have found rest in the Halls of Mandos. But his treasonous actions prevented that. Thus, Saruman's spirit was forced to wander the far reaches of the universe. A passage from Unfinished Tales, explains it best: When "[Saruman] was cast down … his spirit went whithersoever it was doomed to go, and to Middle-earth, whether naked or embodied, came never back."