Warning: spoilers for Suicide Squad are in play. If you don't want to be spoiled, bookmark this page for future reading and come back after you've seen the film.
Among all of the plot points that David Ayer's Suicide Squad glossed over, one of the most vexing has to be that of Katana's decision to turn her back on Rick Flag in his hour of need. Considering how Katana is one of the only actual heroes on the Squad, and her loyalty lies with both Flag and Amanda Waller, you'd think she'd stay true to her mission to the end. But as Karen Fukuhara explains in her own words, that loss of loyalty wasn't just a random or cowardly decision, it was one out of personal integrity.
ComicBook.com caught up with Fukuhara, and she discussed the reason for her character's big moment during the film's second act, explaining the difficult logic of the moment as follows:
Originally operating under the illusion that she and her Suicide Squad compatriots are evacuating a high value target, while combating the menace that is the army of the Enchantress in Midway City, Katana and her teammates are surprised when they find out that their mission has always been about evacuating Amanda Waller. With the mission looking to be nothing more than Waller persuading her temporary lackeys to act against their own best interest, in the name her own, she effectively causes the group to distrust her - Katana included.
While Karen Fukuhara's explanation for Katana's abrupt exit from the Suicide Squad's mission makes plenty of sense, it really is something the film should have covered a bit better in the actual context of its story. Rather than rely on the actor behind the role to divulge the truth about her character, those involved in the film's re-shooting / re-editing fiasco should have included this detail in the film somehow. Instead, the audience is witness to a character leaving the team just as quickly as they had joined it, and with even less context. Let's hope that if and when there is a sequel to Suicide Squad, they'll give Katana some more time to shine on her own.
That said, Fukuhara's performance as Katana is still pretty kick assed, and Suicide Squad is still a fun film to watch, despite its massive flaws. You can always see for yourself, be it your first or fifth time, as the film is currently in theaters.