The Leader...?

Unlucky

Sayaka Maizono: Stabbed in the bathroom, left to bleed out on the tile floor. A liar.

Leon Kuwata: Strapped to a pole and pelted to death by baseballs. A liar.

Chihiro Fujisaki: Blunt force trauma to the head for wanting to be stronger. A liar.

Mondo Owada: Compressed into a salty butter. A liar.

Kiyotaka Ishimaru: Hammer strike to the head. A liar.

Hifumi Yamada: Faked his death, then was killed by a hammer strike. A liar.

Celestia Ludenberg: Otherwise known as Taeko Yasuhrio. Lit on fire and hit by a truck. A liar.

Sakura Ogami: The traitor. Poisoned protein shake of her own accord. A liar.

Mukuro Ikusaba: Has been dead for a long time, acting as her sister. A liar.

They all had died, during this killing game. That was the truth of the matter. All of them had been liars in their own respective ways. Only six of them were left. But that's what they had thought. It had really been seven. 

Junko Enoshima: The mastermind. A liar.

It had been quite the surprise when she had suddenly showed up out of the blue. After all, they had thought she had died a long time ago. They'd seen her get viciously impaled by dozens of steel rods. But there she was, alive, and the creator of this game.

Makoto Naegi: Crushed to death...? No, that was a lie.

Makoto was alive. He cheated the execution that was unfairly put upon him. Kyoko had brought him back up to face the mastermind. Junko had an obsession. It wasn't healthy.  Junko had tried to keep the game going, in order for despair to continue on. But Makoto had shut her down, and stopped her plan in her tracks. 

She had been so full of despair, that she executed herself.

Junko Enoshima: Strapped to a pole and pelted by baseballs. Compressed. Lit on fire and hit by a truck. Crushed to death. A liar.

There were only six students who remained alive in that game. Out of sixteen, that wasn't that many. But, it was the best they could do. The six students opened the door to the outside, and found the world in shambles. It was broken. Destroyed. Whatever had happened before suddenly came back to them. They recalled what had happened here only a little while ago.

They had locked themselves inside this building. It had been their choice, but one of the people who had hidden in the school with them had been the Ultimate Despair herself. That was the whole issue with this killing game. it was always going to happen, since the mastermind had been there from the start.

Makoto looked across the horizon, horrified. Is this really what's happened while we've been in there? Makoto stepped out of the door, assessing the campus. It was empty, and there was rubble scattered a bout. "Is this... really what's been happening after all this time?" Makoto looked around in utter shock.

"It must be," Kyoko observed. "That would be the obvious deduction."

"W-W-Well what are w-we supposed to do n-now?" Toko stuttered. The group remained silent, unsure of what to do next. "A-Are we s-supposed to just h-hang around here u-until we d-die?"

"That can't be right." Byakuya interjected. "There's not point in living a killing game if we just die immediately afterwards."

Kyoko sighed. "Then what are our options? We have two right now." She said, raising two of her fingers. "One: we explore. Try to find other people. Or two: We go back in there." She pointed at the school.