Trigun
"Everyone who has become involved with him has somehow gained an emotion they had once lost."
Trigun began as a sci-fi manga with a wild west theme written by Yasuhiro Nightow. It was later adapted into a 26 episode anime. After falling from the sky the human race starts anew on a dry and dusty planet. The story follows expert gunslinger Vash the Stampede, also known as the Humanoid Typhoon. He has a $$60 billion bounty on his head because he leaves a path of destruction wherever he goes. As a result he is constantly followed by insurance girls Milly and Meryl so as to minimize the damage. A long time ago Vash made a promise never to kill, but when a band of bounty hunters called the Gung-Ho Guns repeatedly attack him Vash struggles to keep his oath. As the story progresses Milly and Meryl find out more about the strange Vash and how they came to live in a desert wasteland.
"You killed them. Even though they did terrible things, the decision of who should and who should not live was never and never will be yours to make!"