So I'm in the middle of writing an outline for my story and I'm having a bit of trouble with one of my characters.
My plan for this character is that he is the antagonist, but by manipulating the MC he is put in the mentor role for a while. Until the MC, with the help from one of my other POV characters, finally realize that he really is the bad guy.
The character will be a dragon in human form, and will only appear in human form to my MC. He will be responsible for training the MC and teaching him magic. They will travel together and free/recruit slaves to fight with them.
The other POV character however will see the antagonist for what he is, seeing him in his dragonform and realize what he is and what his goal is (chaos and destruction).
My problems are, 1 - I don't know how to portray this character and his manipulative ways.
2 - I want to keep the mystery for the readers aswell and reveal the character for them and the MC simultaniously, but my other POV character needs to find out the truth beforehand. I feel like it would be sloppy to mention it at the crucial moment like "hey I saw him 150 pages ago and he is an evil dragon".

Ugh, I feel like this was just rambling, but I hope some of you get what I mean and have some tips for me.