When Bruce Wayne was gone after the events of Endgame, the streets were left unprotected for a while. Once crime came back, there was no one to stop the thieves, not even the heirs to the bat.
So, a bunch of kids and teenagers would come together to form a group with the sole purpose of saving Gotham from itself in honor of Batman and what he had done. They called themselves Robin, as it was Robin, in their eyes, that was the true heir to the Batman legacy. And since they all wanted to do what Batman did, they would always claim...We Are Robin.
This group would have much success, even being deemed as big a threat as to lure the Court of Owls into taking them down. That didn't happen, but the danger was very real. Led by Duke Thomas, the Robins had a very big impact on the DCU.