Add an apostrophe to the first word: There’s (contraction of There is) not Theres (not a word).
Replace in with Of. (Notice that it’s capitalized as the first word of a sentence.)
Change 38 to thirty-eight.
Change your to you’re.
The pronoun them has an unclear antecedent (which is how grammar nerds say, ‘You aren’t clear about what this pronoun refers to’). I recommend replacing it with a noun or phrase. The whole sentence is awkward, though, and may require a rewrite.
Everytime is not a word; change to every time.
Change the comma after sleeve to a period.
Capitalize How. (Actually, I suggest replacing How come no one expects with Why does no one expect.)
Who is this they who never listen? Clarify or reword.
There’s not much known about you. Of the thirty-eight trillion bounty hunters across the galaxy, you’re the one who never fails. Maybe the surprise factor is what makes it so easy for you to capture your targets. Maybe you have tricks up your sleeve. Why does no one expect you, of all people? Young and old, rich and poor have said it many times, but some people never listen. “Beware the one in clown makeup.”