How about "Rush in and die, dogs!"
You could run the whole thing, "Rush in and die, dogs. I was a man before I was a king." But you'd be over the 46 characters. You could fit it in if you trimmed the punctuation and made "before" into "b4", but that's kind of lame if you ask me.
There are quite a few Conan quotes throughout the RPG book and sourcebooks.
REH's Conan stuff is great for quoting, especially if you're not offended by the racism and mysoginy.
Be sure to let us know what you finally go with.