Robin

Tim Drake was in the audience the night the Flying Graysons were murdered, where he witnessed Batman leap to the scene. Inspired by Batman's heroics, Tim closely followed the chronicles of Batman and Robin. Eventually deducing their secret identities using self-taught detective skills, Tim convinced Bruce Wayne and Dick Grayson - now Nightwing - that a new Robin was needed in the the never-ending battle for justice. Tested by the Dark Knight himself with a grueling training regimen, Tim earned the right to become Robin, and has since lived up to the name.

After Arkham
After his mentor's horrific night at Arkham Asylum, Robin alongside Alfred continued to help with uncovering dirt on Hugo Strange, although Batman said it was too late knowing that Strange probably had a back up plan. Tim also entered Arkham City himself a couple of times.

The first time he ended up jumping into a fight with Harley Quinn after seeing them jump some inmates for their meds. After easily defeating her henchmen, he faced off against Harley and easily defeated her, then quickly rushed back to the Batcave thinking that no one noticed.

After surfacing to the manor, Bruce asked him about his patrol to which Tim nodded and said everything was good, only for Bruce to throw his shuriken on the table and while he told him to be more careful where left them. Not wanting Strange's men to bust down their door, he implied that he should keep going.

Batman: Arkham City
As Batman is looking for Ra's al Ghul by following one of his Assassin's blood trails, he is ambushed by three of the Assassins. Just as things are looking dire for Batman, Robin whistles, catching the Assassins off-guard and flooring them with a few quick swipes of his staff. The lead Assassin, who has a sword at Batman's throat, tells him to get Robin to stand down, even though Robin says he can take her. Robin then gives Batman the Line Launcher as he is given a vial of Batman's Titan-infected blood. He goes to the rooftop and leaps off.

Later in Wonder City, you can hear Robin via the comm network. He says that the Titan-blood could be in at least 2000 people by the morning, with the first fatalities expected soon after.