The river Styx.
The swear word is a euphemism for excrement.
The river styx, according to greek mythology, is the only river in the underworld, and for some reason the most popular but the must sacred. To the gods there was no oath more sacred than to swear by the river styx. The river is said to be served as the crosswroad where the living world met the world of the immortal. Some say that it's so foul that if you drink it you will receive instant death, others say that it bubbles fire.
If by "Swar" you mean swear, then he does it because it's who he is. I mean there are people who swear and some that don't :)
cack? Do you mean cake? Why would cake be a swear word?
I Swear to god
To say something bad
prostitute
It means: I swear to God
I promise or swear
Geographically, the underworld is surrounded by a series of rivers: The Acheron (river of woe), The Cocytus (river of lamentation), The Phlegethon (river of fire), The Styx (river of unbreakable oath by which the gods swear), and The Lethe (river of forgetfulness).
well, it depends on what u mean by that if theirs no meaning then yes, u can swear whenever u like although its not good to swear AT ALL