You can understand and say one of the most famous phrases by Luffy in One Piece.
(I am) the man who becomes the king of pirates.
This has been quoted from One Piece.（アニメ ワンピースからの引用）
One by one
海賊（かいぞく） → pirate
王（おう） → king
に → no meaning
なる → become
男（おとこ） → man
だ → is
Note 1: だ and です
だ at the end can be です. です and だ have the same meaning which is ‘is, am or are’.
The difference is です sounds politer than だ.
だ is also used amongst friends. Luffy uses だ as he may say the sentence to his friends.
Note 2: おれは
In One Piece, Luffy usually says おれは at the start of a sentence.
おれは means I, which is used by male and can sound a bit rough. わたしは is the most common word for I.
You can add おれは at the start of the key sentence as that sounds like Luffy: