Tim Drake, aka Red Robin. The third Robin and the most intelligent of the four

Tim Drake approached the batmobile donning his Red Robin costume as Bruce suited up into the Batman.

The young detective was visiting Bruce since the massive crime wave seemed to be taking its toll. He figured the dark knight could use his skills once more. He was the one that figured out that Bruce and Dick were Batman and Robin after all. Batman became noticeably more violent after the death of Jason Todd but Dick had already moved on to lead the Titans as Nightwing so he refused to rejoin Batman. After saving them both from a close call with Two-Face using his intellect rather than his brawn, Batman took Tim under his wing to become the third Robin.