I am going to attempt to write a story. Future humans have polluted the Earth far beyond repair, and they seek to create/alter humans (not sure yet) to survive in the harsh new climate. For some reason, a scientist is going to design the people like vampires (not sure why yet). Regardless, the remaining humans will be driven under the earth in caves, and the vampires will create an extremely capitalist society - by which the weak are consumed by the strong. I know it is an oxymoron to create realistic fantasy, but I am seeking information on a few things. Firstly, is their a way vampires, by drinking blood, could somehow benefit themselves? Does human blood contain something that, during extreme pollution, people could need it to survive? Additionally, if humans were driven under the earth, how would they evolve to live in such a situation - if you were to guess? Finally, I am planning on making the air quality diminish greatly, but this will only effect humans. The vampires will have little idea about human culture and evolve with humans as a background that they consume. Anyway, if you can help me in any way, I would appreciate it. This is biology related, but I have no problem if the thread is moved.