"Oh cute, is that your girlfriend, she's hot, have you fuc...
"Shut your goddamn mouth, or I'll do it for you!"
Robin stepped forward and suddenly stopped, the Joker wrapped his hands around the young boy's throat.
"Ah, ah, ahh, you wouldn't want this boy's neck to turn to jelly, now would you?
"Stop!" said Starfire.
The Joker said "Oh what the hell." he tightened his grip on the young boy's neck who was choking for air, the Joker then snapped the boys neck severing his spine, he dropped the boy and yelled
"oops, god I have such butter fingers", he laughed and fell to the floor.
Starfire gasped and turned her head, she began to cry into her hands. Robin was frozen with anger and fear, he just let the little boy die, he could have stopped him, he could have done his duty and saved a life.
"Your finished." were the only words Robin could muster. The Joker jumped back up and laughed,
"What do you mean, you gonna beat me up, then send me back to Arkham, ha ha, go ahead I'll just escape and torment Batman like I usually do.
"No not this time, you've hurt to many people, you've killed thousands and now you've killed an innocent little boy, right in front of me!"
"Ah come on Rob, it was all fun and games, no one got hurt, he turned his head and pointed at the lifeless body of the boy,
"Well except for him of course." the Joker said maniacally laughing.
"No, I'm going to do what Batman was never able to do, I'm going to kill you!"
The Joker stood up and his face turned into a frown, Robin shot his grappling hook around the Jokers neck, he jumped over him, the Joker grabbed the string around his neck and he actually seemed worried,
"You wouldn't!" said the Joker
Without answering Robin threw the Joker out of the window, still holding on to the grappling shooter. As the joker was falling he thought to himself
"The little shit actually did it., well I had a good run."
His frown turned into a smile and as he was about to hit the pavement, Robin pulled back on the string, snapping the Jokers neck, Though the sound came from far away it echoed through the city, leaving all the Titans who had run up the stairs and stood at the doorway scared and shocked. Robin let go of his Grappling hook, dropping the deceased Joker to decay in his now safe city. All of the Titans were unable to speak except for Starfire who said
"What have you done!"
Robin slowly turned to the others and then at the boy's face which still looked terrified though he was dead.
"I thought there was only good and evil, that the difference between people was there are some who committed crimes and other who stopped it, the sides were supposed to be opposite as different as day and night, the line was always clear, at least it was supposed to be."
His friends began to disappear one by one, he would have stopped them but he knew why they were leaving, he had crossed the line, one which from he could never go back. The last to leave was Starfire.