1.
Variant of kthxbye and kthxbai, but with a mordant edge.
The original term kthxbye (okay, thanks, bye) is generally used to terminate a (n online) conversation in a quick manner, often with slight insult to the other party. The implication is that the other person is not even worth talking to.
kthxdie is like that, only more so, and with an added death wish.
Obi wan Kenobi: You can't win, Darth--if you strike me down, I shall become more powerful than you could possibly imagine.
Darth Vader: kthxdie.
2.
like kthxbye only with a bit more edge/wit
I just had sex with your mother.
kthxdie
3.
kthxbye but misread as kthxdie
okay thanks die
bob your an asshole kthxdie
See die, okay, burn, thanks, kthxbye
