Yeah, it's kind of hard to miss the theme of mortality in this myth. Death himself, a.k.a. Thanatos, actually shows up in person, so there you go. The quest to escape his own death is Sisyphus's major driving motivation. You have to hand it to the guy, he does a better job than most of us would, escaping from the Underworld not one but two times. (Not too shabby.) It seems to us that Sisyphus's quest to escape death is all too human. It's not like it's something that too many of us are looking forward to. Who wouldn't do their best to escape it, if it were in their power?
Sisyphus is one wily dude, who doesn't think anything of manipulating those around him to get what he wants. Whether he's seducing his niece, toying with his wife, or fooling Death itself, Sisyphus is known far and wide as a trickster extraordinaire. In the end, though, Sisyphus learns the lesson that no matter how many clever manipulations he can concoct, he's just never going to outsmart the gods.