Here’s a name even non comic fans should know, kind of because it is the subject of many jokes. Anyway, it’s Dick Grayson.
Origin: Again, most people know this so I’ll keep it short. Dick Grayson was a trapeze artist with his parents, the Flying Graysons. They were killed during a show, so Batman adopted him as Robin. Dick eventually left to lead the Teen Titans as Nightwing, his most well known hero name.
Life: Being a very old character, there is a lot of stories in Dick Grayson’s life. After he left the Titans he went to his own city, Bludhaven, which is much like Gotham. Bludhaven was destroyed in Infinite Crisis, when Chemo was dropped on the city. Dick spends some time in the irradiated city, until Final Crisis happens when he becomes Batman. In the New 52 Dick is Nightwing for a long time until Forever Evil where he decides to join an agency called Spyral as Grayson.
Why he’s on the list: Dick Grayson is the heart of the DC Universe. He is the one thing that convinces Earth 2 Superman that Earth 1 is worth saving in Infinite Crisis. Bruce considers him the one thing he knows he did not mess up. When he is Batman he brings a more human side to it, showing weakness and concern for how he’s raising Damian. Dick has had the most close calls with death, because no writer wants to write a story where Dick dies.
Recommended reading: Infinite Crisis, Forever Evil, Batman and Robin (Grant Morrison)