Why is Dimentio framed as the antithesis to Luigi?

In chapter 8 of Super Paper Mario, the 4 heroes fight who I see as their antitheses. Bowser and O'Chunks are both unintelligent and brutish, but Bowser is able to recognize what is in his own self interest. Peach and Mimi are both viewed by others as innocent and incapable, but Peach wants to disprove this characterization while Mimi deceptively plays into it for her own gain. Mario and Count Bleck are both the intelligent leader of their respective groups who are only determined to reach their end goal, having nothing to prove and no ulterior motive, but Mario's goal is to better the world while Bleck's is to end it. Following this, it would imply Dimentio is the antithesis to the character of Luigi. How is Dimento the anti-Luigi?