The Dark Factor of Personality (D) has been suggested as the basic disposition underlying dark traits, thereby representing their common core. However, it has also been argued that such commonalities reflect the low pole of Agreeableness. The present study (N = 729) employed five established inventories to model the Agreeableness construct and considered seven theoretically derived criterion variables, including one behavioral outcome. Results indicate that Agreeableness and D exhibit a substantial, but far from perfect, association of r = −.64. Further, D incrementally improved the prediction of all but one criterion measure. These results speak against the notion that the commonalities of dark traits can be reduced to low Agreeableness and rather support the contention to consider Agreeableness and D as functionally distinct constructs.