For years – really ever since Revenge of the Sith was released – I’ve heard people criticize Obi-Wan for walking away from Anakin on Mustafar.
Obi-Wan was sent to kill Anakin, he managed to defeat Anakin by slicing off all but one of his limbs, and then just … leaves? Why not just mercy-kill Anakin? Why not heal Anakin (since that’s a thing now, apparently)? Why not anything except leaving him there to die slowly?
I was 14 when Revenge of the Sith was released. Even if I hadn’t read the novelization, I still would have seen the answer as obvious, as a 14-year-old. But the novelization does spell it out for everyone: Anakin did not deserve the mercy of a quick death. The novelization itself said that. Also keep in mind the fact that Obi-Wan didn’t want to watch Anakin die with his own eyes and probably preferred knowing it would happen on its own soon.
Let’s look at it logically, though…
Obi-Wan was sent to Mustafar to kill his old apprentice, and the moment before their battle, he said, “I will do what I must.” Obi-Wan saw “a security hologram of Anakin killing younglings.” (I can’t even write that without laughing.) Anakin assisted in driving the entire Jedi order to extinction. He helped usher in a tyrannical government. Anakin didn’t just kill hundreds, he didn’t just cause the death of thousands, but all of his victims were innocent people, especially the ‘younglings.’ Oh, and Anakin was going to be a father… GREAT kind of guy to have raising children, ammaright?
So, no, Anakin did not deserve a quick death. He deserved to die alone, burning, and helpless.
It’s not like Obi-Wan was thrilled to let his old friend and apprentice suffer. He openly showed Anakin his agony and heartbreak. Obi-Wan did what he must, just like he said.