Joker shoots Barbara Gordon. The injury that paralyzed her, ended her career as Batgirl & paved the way to her becoming Oracle (from the graphic novel Batman: The Killing Joke by Alan Moore and Brian Bolland)
First full trailer to Justice League VS Teen Titans revealed and oh boy Damian is really his fathers son. These movies have done great developing Damian also in Batman Bad Blood we saw that Nightwing is dating at least at the time of that movie Starfire.
Nightwing with his childhood love, Oracle. When she was younger, she was Batgirl while he was Robin until she was paralyzed by a bullet that severed her spinal cord. Ever since, he has taken care of her. They have loved one another since childhood.