In a rare occurrence for Attack on Titan, Connie actually doesn't end up dying. After Eren is finally defeated in the final battle of heaven and earth the power of the Titans is finally eradicated, resulting in Connie reverting back into a human along with his other comrades that survived.

Does Connie turn into a Titan?

Like his mother, Connie was transformed into a pure Titan through the direct and implacable will of Eren Yeager. ... After Springer returned to normal, he was rejoiced to hear that he could reunite with his mother (and without child sacrifice, no less).

How many Titan kills does Connie have?

Although Conny is usually considered to be among the dimmest of the group, his speed is such that he almost never has to actually involve himself in a real fight. He has, however, scored one Titan kill, as well as murdering twelve people across the anime and the manga storylines.