In the passage, Johnny is characterized as?

Johnny Cade is the second-youngest in the greaser gang, besides Ponyboy. He is "smaller than the rest, with a slight build. He had big black eyes in a dark tanned face; his hair was jet-black and heavily greased and combed to the side, but it was so long that it fell in shaggy bangs across his forehead. He had a nervous, suspicious look in his eyes... He was the gang's pet, everyone's kid brother."

But after being beaten badly by the Socs four months before the action of the story commences, he is "jumpier than ever." He was always "high-strung," living in a household where his parents beat him all the time. When the Socs attack him and Ponyboy, he kills Bob to stop them from drowning Ponyboy.