Eris is probably the overarching antagonist and Aphrodite the main antagonist.

Yeah, Eris’ role is pivotal but indirect. Aphrodite and Paris are more involved.

The former is likely the Big Bad and the latter The Heavy.

To anyone who says Eris, I would point out that she isn't actually in the Illiad: the whole 'Apple of Discord' story comes from the Cypria.