Gotham's crime fills the air like toxic gas. It needs a hero, someone to protect Gotham as a priority. This somebody was Bruce Wayne. When his parents died, he needed to do something that they would be proud of. That day, the bats were a symbol of fear to him. So he became one of them as...the Batman.
The one bad thing about Gotham is that many people are on the side of crime and not many doing the opposite.
Luckily they have someone good, the Batman. He was driven by fear but then the need to save this corrupt overtook. He has changed to a crime fighter...the best there is with no powers.