There was never three sets of chains in their prisons.

There was four.

Black was the darker side of Blue, just like Red to Sans. In the fourth corner of the room he had sat, chains connecting him to the wall just like everyone else. Black had been the third skeleton to escape, trailing after Blue and Red. He had been the skeleton to shush Red when the skeleton interrupted Flowey and Blue, he had been the one to try and stop Blue.

Black was the one who fought the most. He was the only one confident enough to stand up against him from the start, and he had been the most disliked by Papyrus. While Red was more different looking, he was still scared of Papyrus. Red didn't dare fight back. Not Black, no. He was the one who bit at Papyrus when he tried to get too close, he was the one who constantly tried to break his chains.

Papyrus hated him. It was obvious to all of them. He hated how easily inclined Black was to attacking, how foul mouthed he was. Red had been trained by his own Papyrus to hold back, but not Black. Black was probably the strongest willed out of all of them, he was the only one in their old prison, in their old universe, to try and kill Papyrus.

The first attempt had been with the fork he had been given to eat his food. Black had tried to stab Papyrus, failing as Papyrus had rather expected it. From then on, they were only given plastic utensils to work with.

The second attempt was taking advantage of his chain, using it to trip Papyrus and try to attack him on the ground. That also did not work, and his own chain was shortened. Papyrus had hummed that good "toys" get to keep their privileges, and had said that while petting Sans' skull. Blue was pretty sure Red had thrown up.

The third Black had been desperate, it was his last before Undyne had given Blue the key. He didn't have a plan, he just attacked when Papyrus tried to feed him, scratching his sharp fingernails down his face in order to try and hurt him. Papyrus got a scratch, it was the most damage any of them had gotten so far. It had been a beacon of hope.

Until, of course, Papyrus had compared Black to an angry kitten, then had refused to feed him for a week. That had really drained Black's strength, and washed out any sense of confidence until he was literally begging at Papyrus' feet for food.

However, obtaining the key had given Black new hope. There was people out there, help! They had escaped once before, and they could escape again.

And Blue still had the knife.

Black had been the first to be grabbed by Papyrus, struggling frantically. Snow was kicked up as he managed to elbow him, soul becoming blue before Black was forced to the ground. Blue tried to reach for the knife, but decided to keep back, trying to reason with Papyrus.

It failed, naturally. He was so stupid back then, thinking anyone could be a good person. Papyrus loved them too much to even try.

The reasoning got nowhere as both Black and Red tried to fight him off. It wasn't just a fight for freedom, it was for survival. If they went back, they were all goners. This was their once chance to escape, and...

Well, he had ruined it. Blue had absolutely ruined it for all of them. He realized that as he sat there, watching Red and Black try to fight without any magic.

He was an idiot.

But there was still a small chance, right? If Blue pointed out the logic, he could strike a deal maybe! Papyrus would always be fighting them, so maybe if one of them went willingly, he'd let the others go! Then he could get the love he always wanted, and the others could go back to their universes!

Blue was about to make the offer before Black had gotten his hand on a nearby stick, giving a firm attack with it. The stick didn't provide much damage, but it was something more than what he was doing previously. Red had been shoved away at this point, stumbling back into the snow.

Black was thrown down as well, reaching out for the stick, hand fumbling out. Papyrus pushed his own foot against his arm, causing a creaking sound as Black's arm was forced against the ground, the skeleton crying out in pain. He looked up, spitting out insults, flailing uselessly.

"You look nothing like my Sans," Papyrus sighed, tilting his skull. "And you act nothing like him. You're as useless to me as Undyne."

He then straightened, and lifted an arm...

Lifted his arm...

~~~~~~

Blue stifled a cry, forcing a hand against his teeth as tears gathered in the corners of his eye sockets. He pulled at his collar, as if trying to escape the memories plaguing him.

"Blue?" Gwen asked.

She found her own voice quiet. Barren.

Scared.

"Papyrus killed him," Blue choked out, "And it's all my fault."