[quote=@harinezumikouken]
[@Triple A] - I like you.

Also, Shiro is written to be able to die. If that makes any sense.
[/quote]

Meanwhile, Robert is written to be immortal. He's the [url=http://tvtropes.org/pmwiki/pmwiki.php/Main/BornUnlucky]Born Unlucky character trope[/url] incarnate. Unable to die because the universe is nowhere near done torturing him.