Actually 1eyed... if I had come across either of those things you said in a video game/novel/message board, my face would be firmly planted against keyboard. That's horrible horrible writing there.
And since we've established you can't say that without some backup, let me see what I can come up with...
"A trail of corpses follows my wake, and not even the red dawn can paint the blood I have spilled over the land. Move aside."
"My sword, Bloodbath, is barely sheathed, fools! Do you want to learn the meaning of its name?"
"The only coins you'll get from me are for the Styx's boatman"
"You'll have two over your eyes before I finish my sentence."
These statements aren't very "badass", and in fact, I think if they were ever said in a dialogue, you have as much of a chance of stumbling over your words as actually intimidating someone. It's overly verbose and likely to be misinterpreted.
I may reply (if I were feeling smart-assy) "I didn't know Styx had a boatman, I thought it was just a guitarist, drummer, and lead singer". And then where would you be? I mean, you may end up killing me, but your comrades would be laughing about you at the campfire that night.