In Justice League (2017), Steppenwolf figures out that Wonder Woman has "the power of the Old Gods". He then derisively remarks:
The Old Gods died.
But I don't see how he can know that. We see the Old Gods (including Ares) fighting against Steppenwolf's original invasion, so we know that it took place before Ares killed them all. It's possible that some of them died during Steppenwolf's invasion, but he seems to be aware that they're all now dead.
How does Steppenwolf know this? Did he just deduce it from their absence? Or is this a continuity error?