It's simple. (Spoiler alert) Like Ares said in the film when he confronts her, he says, “Only a god can kill another god”. It does have precedence in the comics, for example, Diana killed Ares in Rise of the Olympian. read more
It does have precedence in the comics, for example, Diana killed Ares in Rise of the Olympian. However, gods can’t truly be killed as shown by Greek mythology, but the filmmakers probably wanted some stakes and finality added to the story. read more
But the execution comes off a little ridiculous, and it’s made worse by the fact that the third act, and specifically the battle between Ares and Wonder Woman, runs on a little too long. Also, the defeat of Ares raises more questions than it answers. read more