3. "Him": Mysterious evil dude. Try combining him with some animal that might be considered evil. (Rat, hyena, cat, clichéd snake, an evil chicken, a hell-moose, a fish, ect. Whatever, just have the finish evil). Why is he mysterious? Give him a tinge of crazy (Does he dress like a woman? Why? Those are lady's clothes. Is cotton really that uncomfortable?) or a flawed philosophical belief (“He” some how believes it’s okay to kill people, or at least steal and brainwash infants) Something must be wrong with him.
4. The Twin Brother: Should be the same age as the Young Woman (unless you can convince otherwise; time traveling brother who lost his memory and found by “Him”?) Was he harmed during the incident also? Does the Young Woman know the relationship? Are they fraternal or identical twins? Why doesn’t he want to fight on the side of his sister? (Is he completely under the control of “Him” or does he strongly believe in “He” to be the real hero? Or Does he not know they’re related, why? Scars or does the young woman’s costume not reveal her face?)
DON’T create the parents, they’re flat characters. (Unless you really want to show there deaths. You sick m#@%&#$ F$)$er.)
For the environment folks: Uncle’s lab, “His” lab, The young girl’s or twin brother’s training ground, The destroyed family home (probably easier to design the undestroyed home and then destroy it). Sorry, I’m a character guy, environments are a bit strange to me. Argg! I’m too wordy!