In my current WIP I have an anti-hero/villian (female) who will butt heads with the MC often. The MC is an FBI agent and the villian, an assassin. There is also a second villian that is a bomber, who is male. Early in the story, the MC believes the assassin and the bomber are the same. My questions are: 1) Is it possible for the assassin's gender to stay hidden from the readers as well? I have tried to do this but most of my paragraphs are filled with "the assassin this" or the assassin that" . I tried assigning a name to the assassin but that only slightly alleviates the problem; now I switch back and forth between the two. The writing seems clunky without the use of pronouns. 2) If it is possible, is it even fair to the reader? Should the reader be in on it and allow them to watch as the agent finally discovers the secret they have been privy to? Is not revealing the gender to the reader too gimmicky? How much should the reader know that the MC doesn't? And vice-versa? 3) On the subject of deceiving the reader, is it bad form to use "he" in a gender-less form; seeing how the English language doesn't have a singular non-gender pronoun? 4) Since the assassin has much more story written in the book, should I just leave the bomber as "gender-less"? I know that's a lot of questions, but I've been struggling with this. Thanks in advance for any and all help.