After a very emotional reunion, the princesses let him stay on the room that Rarity normally occupied. The room was extremely fancy and very well decorated, he didn't have to much objects with him, except for his cellphone, his clothing, and his favorite book.
He always liked 'The little prince' since it was the first book he managed to read by its own. Maybe it was for the amount of drawings that contained, maybe it was for his fathers recommendation, maybe it was for the fact that he really liked his clothing, both of them, but in a hard time like this he knew that he couldn't sleep, so will read it instead.
He started reading, and he immediately was trapped on the story, again. As he read it the sunset was replaced with stars, the moon, and the beautiful darkness of the night. Although he really wanted to know what happened to the world in all these years, he preferred not to do it tonight; tonight he didn't felt strong enough. Tonight he was nothing against the fact than his whole species was extinguished, except for him.
Now that he was starting to remember his time with Celestia and Luna, he was wandering: "Did I do the right thing? Was correct to take care of them, even though they were a danger to the world?"
Tears began to fall on his face again, he left the book aside, and focused on sleeping; or at least trying to sleep that night. He tried to convince himself that he did the right thing, and that what happened was a simple accident, although it was pretty hard since now he remembered the last time he saw his mother.
Two days before Celestia's kidnap, his mother left him in charge of the house, her sister, and the two little 'alicorns', since she had to go in a business trip, he now was 17 and proved to be responsible in the past, so she trusted him.
"I'll be back in a week." she said. "Don't let anything else happen to Tia an Luna."
"Don't worry, they tried to kidnap them before, and they always failed." William said. "They can fly, run very fast, and now I just teach Luna how to teleport."
"Ok, See you later Tia." she said as she gave a hug to the withe alicorn. "I'll miss you Luna." she said as the black pony enjoyed her hugging time. "Don't forget to be nice Melisa, and do everything William says."
"I'll do, I'll do." William's sister responded.
The family ended hugging each other without a concrete order, all of them thought that in a week they'll reunite. But they were wrong.
William finally stopped remembering, since it was painful to know that he failed. He wanted to go back in time, go back and fix all this huge mistake, but he can't.
"I can't believe it Tia!" said Luna to her sister. "After all those years he is still alive! I was about to lose the hope."
"But he returned back." said the white mare smiling, but her smile faded a second later.
"What's wrong?" asked Luna to her.
"Did you remember when he left us?" asked Celestia. "All the pain, all the fear of being alone, all the sadness of watching the human civilization fall before our eyes."
"Yes." said the dark blue mare. "I remember when we found Melisa as a pegasus, we were so scared and lost than..." then the mare realized. "Oh no, William is going through the same thing as you and me, if not worse."
"Exactly" said the white mare. "Although I gave him a room at the palace, it wouldn't be enough for him, I know him. He wants to see everypony happy, and he wanted to see his mother an sister happy as well. But now he lost them."
"I've an idea!" said Luna. "Maybe I can go into his dreams; try to calm him, gave him comfort, and banish the nightmare that he probably is going through."
"Oh a nightmare." said Celestia a little scared. "Well this is certainly more your terrain than mine. Well don't lose more time. He needs you!"
"Ok Tia, I'll go." said Luna with determination on her voice. "Is the least I can do for all the times he comforted us from all those nightmares of the lab. Maybe he could help me with the tantabus problem."
"What problem?" asked Celestia with a raised eyebrow.
"Nothing!"
Luna was starting her spell, her horn was glowing white as she entered the dream realm. In there, she saw tons of doors than leaded to the dreams of everypony in equestria, various and daily dreams she already was used to.
But there was a new door among the others, and Luna could sense of who it was. As she approached to it, she could see that was a tall, blue, star-decorated door, with a golden round handle.
"Here we go." said the princess to herself as she entered the door.
In the dream, the place was all dark, cold, and empty; except for William, that was at the center of the darkness. But staring at him were 2 eyes in the darkness, one green, and one red.
"NOW YOU UNDERSTAND." said a voice coming from the eyes. "CELESTIA AND LUNA KILLED OUR RACE, WE SHOULD TAKE REVENGE ON THEM!" the entity shouted.
His voice was abnormal, extremely deep and disturbing, but understandable for William and Luna. Speaking of her, she was horrified by this nightmare, she never though of herself as a burden to William, and this statement paralyzed her in a way that she never felt since her time at the lab.
"No!" William shouted to the entity. "Even if some mistakes were made, they were not Tia or Luna's fault, they were from director Osvaldo!"
"THAT'S WHAT YOU KEEP TELLING YOURSELF." said the entity as he left the darkness into the sight of both presents.
He was almost like William, but that thing had one green, and one red eyes without pupils; very long, and very messy hair; extremely big hands, with fingers that look more like claws; and spiky teeth on his mouth. "BUT YOU AND ME KNOW THE TRUTH, SINCE WE ARE THE SAME PERSON." the monstrosity said. "BUT SINCE I AM THE BRAVEST OF THE TWO I THINK YOU CAN CALL ME OWLEN."
The princess already had enough of this 'Owlen' so she was about to undo the nightmare right now, but Owlen spotted her.
"SPEAKING OF WHICH! LOOK WHO JUST DECIDED TO ENTER TO HER DOOM, THE PRINCESS LUNA HERSELF." said Owlen. "TO BE HONEST WITH YOU LUNA THAT TITLE FITS YOU VERY WELL. BUT ENOUGH CHATTING, ITS TIME FOR YOU TO DIE."
"Enough 'Owlen'." said the night mare. "You are just a nightmare, and as one, you have no real power over hi... Ahhhhh!"
The princess couldn't finish her statement, since Owlen extended a claw and levitated the princess from the neck strangling her.
"Luna is it you!" asked William. He knew that Luna could enter in people's dreams, since she already entered in one of his. "What's happening!?"
The princess barely could talk, she didn't knew how a nightmare can do this things to a real pony, until she realized: "William still has all that magic! With all of that power he could unconsciously create entities like the Tantabus!" she thought.
"IT APPEARS THAN THIS MARE WANTED TO MAKE YOUR DREAMS PEACEFUL AGAIN, BUT SHE ISN'T A THREAT TO ME! NOW, HOW SHOULD I KILL HER?" Owlen asked to William. "DECAPITATION, SOFOCATION, DROWNING HER, BURNING HER, OR MAYBE I SHOULD GO FOR THE PAINFUL TORTURE OPTION!"
"W-Wi-William" said the mare almost fainting "If he kills me he-here I'll d-die in the real world."
"Leave her!" said William rushing to Owlen to punch him on the face, but Owlen just levitated him away.
"AND YOU ARE STILL TRYING." said the monster. "EVEN AFTER ALL SHE AND CELESTIA DID TO YOU, YOU STILL TRY TO DEFEND THEM. THAT'S WHY I SHOULD KILL HER, TO SHOW YOU THE TRUTH SO YOU CAN AVENGE OUR SPECIES."
"William." said Luna. "He only has as much power as you choose to gave him. Use your magic to... Mhp." her mouse was closed by a black aura.
"SHUT UP STUPID HORSE!" shouted Owlen. "THAT'S BETTER, NOW, LET THE FUN BEGIN."
William was about to close his eyes to avoid seeing the horrors that Owlen was about to show him, when he remembered: "I've Luna's magic!"
Owlen was about to sink his claws into Luna's face, when a blue light beam throw him away.
"Never! I said, NEVER! Touch her again." William shouted to Owlen as Luna fainted to the floor.
"OH, SO YOU ARE STILL UP FOR FIGHTS." said Owlen. "DON'T WORRY THIS WILL BE FAST."
"I know." William said confident of himself.
Owlen rushed to him almost like an animal hunting its prey. But when his claw was about to hit William on the face, William grab it, and then threw the whole body of Owlen into the ground.
Then his hand glow, and he use it to seal Owlen in the ground until he couldn't be seen. And with that quick movement, Owlen banished from sight.
After recovering the calm William ran quickly to Luna, and tried to wake her up. As he was doing this, the absolute darkness of the dream was slowly replaced by a sky full of stars, and a floor that reflected that as a mirror.
"Luna! Luna! Wake up! Wake up!"
"Umm... what just happened?" said the mare before noticing William. "William! Are you ok, that thing almost killed me! It could have killed you as well, I wasn't sure that you could deal with..."
She stopped before the tide hug William gave her. For that instant all their fears were gone, just for that single instant.
"What was that thing?" asked William, breaking the silence.
"Well..."
"So this 'Tantabus' you faced before, is similar to Owlen."
"Yes." said the mare. "Although he was more sapient, and more brutal than the Tantabus."
"But... he is gone, right?"
"I think so." answered Luna. "But that thing was formed from your negative feelings, your fear, your anger, your hate. I came to this dream to comfort you, and wipe out your fears, although the reality I founded was even more dark than I though. I don't know if I can do this alone."
"What do you mean with 'alone'?"
"I know some ponies that could help with your problem" stated Luna. "In fact, you already met one of them: Fluttershy."
"If you say so Luna." William said with a mixed expression on his face.
"Trust me." the mare said. "They are amazing, they are the elements of harmony!"
"The what of harmony?" William asked.
"Oh sorry, I forgot that you missed a lot of what happened, but I know that with enough time you'll get all the important info!" she declared. "In fact, I'll wake up and wrote a letter to one of them."
"Ok." said William before the princess of the night banished in front of him. "I trust you Luna."
He lay down on the reflecting floor as he watched the stars in his dream. Now he remembered almost everything that happened those years he raised Tia and Luna, he know that at least they had not forgotten him, and most importantly, he had hope. The dream lasted a few hours more until it dissolved as the sun began to rise in the morning.
"Today is a new day." he said. "And at least the 'elements' could help me.
Meanwhile, in William's subconscious, Owlen was trapped, but still angry.
"COWARD! COWARD! THIS WONT LAST FOREVER, SOON I'LL BE FREE, SOON CELESTIA AND LUNA WILL PAY!"