This is a Merlin-Doctor Who-Once Upon a Time fanfiction. Arthur just attacked Regina because she used magic and then he ran off, leaving Merlin with Regina, Emma, Hook, Mary Margaret, David, the Tenth Doctor and the War Doctor.
*****
"It isn't his fault." Merlin said, pacing the room.
"He tried to kill me!" Regina countered. "How can you say it wasn't?"
"It's his father's. My king's. He hates magic. Arthur's mother died because of it, and he decided that any form of sorcery was evil."
"Have you ever tried to change his mind?" Emma asked.
"There have been some examples of good magic. But King Uther never listens to reason anymore."
Ten scoffed. "Reminds me of a few people."
"Are you really a time traveler?" Merlin asked, his curiosity gaining control.
War knew where it was heading. He knew Merlin, although Merlin didn't recognize him. "You can't save her."
Merlin's head snapped around. "What do you mean?"
War stayed silent.
"I know your voice. Who are you?"
"You're not the only one who wants to know, mate." Hook said. "I have a feeling that trouble is the only thing we'll get from these people."
Merlin stared at War, his eyes changing color for a moment before opening his mouth in shock. "No."
War sighed. "It has been many long decades since I last saw you," Merlin looked away. "young warlock."
Ten marched up to War, eyes blazing. "So that's why there's a huge blank in my memory. You spent hundreds of years living in land of sorcery, until you thought you were ready to go back to Gallifrey?"
"But... you're human." Merlin whispered. "When I knew you, you were a dragon."
"You were a dragon?" Emma said, taking a step away.
"And I'm a dragonlord." Merlin replied. "I don't find a lot of things surprising nowadays."
"You still have a destiny, Merlin. A great destiny intertwined with Arthur's. I was never wrong about that." War continued.
"You're cruel."
"I never meant to be. When Uther imprisoned me, you were my only chance. I had tried speaking to the Lady Morgana a few times before, but she never listened."
Merlin began making his way towards the door.
"Merlin, don't be foolish."
"I'm not."
"Merlin!"
He spun around. "In my time, I released you, and you took it out on the whole kingdom. It was only after I found my father and harnessed my powers as a dragonlord that you were stopped!"
War closed his mouth, a pained expression on his face.
"I need some time to think." Merlin said quietly.
He opened the door and left the room.
