Justice League (movie)
Steppenwolf manages to retrieve the Mother Box from Themyscira, prompting Queen Hippolyta to warn her daughter Diana Prince. Diana joins Wayne's group and informs him about Steppenwolf and the Mother Boxes. The two of them fail to persuade Arthur Curry and Victor Stone, but manage to recruit Barry Allen into the team. Stone later joins the group after his father Silas is among those kidnapped, and Steppenwolf attacks Atlantis to retrieve the second Mother Box.