User blog comment:Hawkinz340/Favorite Anti-Hero/@comment-24769684-20140416185354

Antihero means:

"A protagonist who lacks the attributes that make a heroic figure, as nobility of mind and spirit, a life or attitude marked by action or purpose, and the like."

Doesn't Coby have all of those things? The fact that he's been put against Luffy doesn't make him an antihero, just a hero with different ideologies.