Welcome to 'ALT'. That is 'Anime Links and other Things'. This is the section with information on Trigun. Trigun follows a man named Vash the Stampede as he is exiled from his home and forced to leave. After a battle where he was attacked by another man's army (and escaped without killing anyone himself) the entire town had been destroyed; thus making Vash a wanted man. Not only were his enemies after him then; but various bounty hunters were also after the 60 000 000 000 that Vash the Stampede was worth.
Vash finds himself joining new friends and old enemies in the wilderness and the series follows his battling himself, his constantly injured body (he is partly synthetic) and also his enemies without actually harming any of them to cause death.
At one point during the series Vash finds himself so angry with this man named Millions Knives, that he kills him. Moments later he hates himself for what he's done...and then he finds out that Millions Knives had actually not done anything wrong and was innocent...and he breaks down - thus bringing about the end of the series.