When Derek Powers realized that his condition was getting out of hand, he knew he had to protect his company first, to do so, he made a move to appoint his son Paxton to his stead.
What he didn't realize, or failed too, was that Paxton was as corrupt as he was. And he used his fathers illness to not only get the company, but to out Derek's condition, turning him into public enemy number No.1. Then, he teamed up with Batman to try and kill him. Batman didn't approve of that though, and when Blight got loose he tried to kill Paxton. Numerous times.
The two people Blight hates most in this world is Batman, and his own son. Hard to not see why.