Tim Drake, aka Red Robin

Red Robin, aka Tim Drake. Robin III.

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 and he needed a new partner. However, Dick had already left for the Titans and wasn't going to become his sidekick again.

After saving both himself and Batman 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.