The differences between the Contagonist and the Antagonist are best understood by looking at their component character elements.

At the motivation level, the Contagonist represents Temptation and Hinder, whereas the Antagonist represents Reconsider and Avoid/Prevent.

Where a contagonist might lead one astray and impede one's progress, an antagonist would make the argument that one should completely reconsider one's plans while actively acting to avoid or prevent them from taking place.

The same type of relationships between the Contagonist and Antagonist exist in the other three levels of character elements -- Methodology, Purposes, and standards of Evaluation.