Board Thread:General Discussion/@comment-1998684-20181212145135/@comment-1998684-20181212223022

Diagonally33 wrote: Harley was show in Arrow being held in Argus. Captain Boomerang was the main bad guy in the first Arrow and Flash crossover. Arrow season 3 had Ras al Ghul who is Batman villain, also we saw Katana.

But then they weren't allowed to do anymore with Harley following that cameo. Boomerang wasn't in a film yet during that crossover and then they killed him off probably to avoid that crossover. Ra's Al Ghul wasn't scheduled to be in a film yet and we haven't seen Katana in awhile. It's all down to when they did the character and when WB gives them the go ahead.