First we were led to believe that Mera would join the ranks of the Justice League. Well, that didn't happen; neither did the dramatic change in character design promised by Jim Lee.
Then, for Free Comic Book Day 2012, Mera was featured in the Trinity War teaser, as being part of the super-hero scuffle. Guess what? That didn't happen either! Mera was removed completely from the story. To justify her appearance in the 2012 teaser, the most "elegant" solution that could be found was to pretend that Martian Manhunter momentarily adopted Mera's form to... confuse the enemy? What an insult! I cry foul!
Justice League #23
"Trinity War" - Conclusion
Written by Geoff Johns
Art by Ivan Reis - Colors by Rod Reis