You were recruited by a mad scientist…But you already knew what was in store for you, didn't you? - If you believe Mauja is a mad scientist, he was recruited by him. He certainly knew what was in store.
You don't often start things, do you? But you certainly finish them. - Deimos kills things - "finishing" them.
Your colouring will both go through and not go through the Green Glass Door. - Depending on what word you put in, but "dark" will go through and not go through.
Your species will not go through the Green Glass Door. - Unicorn.
Your gender will. - Stallion