A/N: Roman Britain AU, circa 2nd century AD. Teàrlach is the son of a Pictish leader, respected for the powers of his mystical inner eye. Erik is a Roman centurion with a mysterious past, captured by the Picts in the aftermath of a battle. Friendship is unlikely; alliance next to impossible; love, the biggest surprise of all.

(Yes, this is strongly influenced by Michael Fassbender's movie Centurion, but not so much as to warrant describing it as a crossover. Moreover, Teàrlach is the Scottish Gaelic version of Charles - not Pictish, I know, but as the Pictish language is extinct it's the closest equivalent I could find. Also mutant evolution is happening a little bit early here but I'm sure y'all can handle it and Erik for one barely knows about his power at this point.)

only the air you took – part one

They had captured him that very night, he knew. When he felt it, Teàrlach was holding a vigil for a child who had succumbed to fever; something he did not because it was required of him, but for the comfort he knew it brought the living in their time of mourning.

The man's rage was a tangible thing; Teàrlach felt it like a punch to the gut and pressed both fingers to his temple in an attempt to shield himself slightly from the blinding combination of pain and fury and grief.

Among his people, Teàrlach's powers had always been feared and respected - when he was younger, he had been sent to live with a witch who owed her life to the tribe's warriors, and particularly their leader Murtholic, Teàrlach's father. He had learned much there: how to set a bone and treat any number of wounds; the many properties of herbs; the ancient rituals, common and arcane, that their people had followed for as long as anyone could remember. More that that, he had learned from what she was unable to teach him, and had worked silently, on his own, to develop what the witch had called his inner eye.

Tugging his fur cloak tighter around his shoulders, Teàrlach murmured a blessing over the child's body and stepped out of the tent, straightening in the cold night air. Near the village centre he could make out his father's form, standing over a kneeling man who was struggling fiercely in the grip of three men holding him down.

Teàrlach stood in his rightful place at his father's right hand. Wind howled through the tents and whipped his hair about his head, but his attention was focused solely on the strange man who looked unlike any Roman he'd ever seen before.

He said as much, and Murtholic looked at his son. "He is not Roman," he said simply. "You will tell me if he lies?"

Teàrlach nodded, and watched as Murtholic dealt the man a heavy blow across the cheek. The tribesmen roared as the man slumped in his captors' arms, weak from injuries and travel. His eyes burned bright with hate, and Teàrlach found himself unable to look away.

"I am Murtholic," his father said in accented Latin. "I command here. You are my prisoner now, centurion."

The man spat at Murtholic's feet. "Go to hell." His voice was flat, and he spoke in the guttural Pictish dialect of the area. Teàrlach raised his eyebrows in surprise.

Murtholic revealed rotting teeth in a parody of a smile.

"What is your name?"

The man kicked out behind him, aiming blindly for the knee of one of his captors, and earned himself a harsh kick to the stomach that left him heaving and gasping for air.

"What is your name?" Murtholic asked again.

Blood had gathered on the man's lip and was already congealing in the cold. He met Murtholic's gaze, glaring, but remained silent.

Murtholic turned to his son. "His name?"

Teàrlach's finger rose and the men fell silent as he focused, ignoring the wary look the man turned on him. His inner eye could be fickle with the strong-willed, and it took a moment to steady himself against the man's emotional turmoil and plunge past it, deeper, into his thoughts and memories.

"Erik," he said finally. He watched as Erik's eyes widened, then turned back to his father. "The Romans know him as Gaius Crispus, but his true name is Erik."

"Erik," Murtholic repeated thoughtfully. "Certainly not Roman. Yet you fight with them and wear their armour." Erik's struggles had ceased the moment Teàrlach said his name, and he was now kneeling stiffly, staring at the trees in the distance as though by sheer force of will he could transport himself to freedom.

The sound of Murtholic's dagger being drawn broke Erik's trance. His eyes - a piercing blue-gray in contrast with his muddy, blood-streaked skin - followed the glinting metal as Murtholic flipped the dagger in his hand and offered the hilt to Teàrlach.

"Here, my son," he grunted, "show the man how gracious our hospitality can be."

Teàrlach reached for the blade, hesitant. He was not a warrior; far from it, to his father's chagrin, he considered himself a healer. It wasn't unusual for Murtholic to ask his son to draw blood in the name of honour - or merely for the satisfaction of seeing him do it.

"Father…"

"Tch!" Teàrlach knew that noise; it meant he had better step in line and he had better do it fast. Mystic or not, no one disobeyed Murtholic lightly.

Teàrlach drew a deep breath and took the blade. He misliked the feel of its weight in his hand, the bloodstained bone and leather handle stiff and unyielding against his fingers.

"Hold his head," he told the men, and fought back a grimace at how small his voice sounded.

Erik began to struggle again, grunting as a hand wrapped around his throat and two more yanked his hair back.

"Cowards!" he yelled. "Filthy savages!"

Teàrlach pressed the blade to the man's lips, very aware that the less Erik said right now, the better. He would have liked to know more about this Roman who was not a Roman, but it was taking all his will to hold back the crashing waves of rage and fear and pain rolling through his mind, and his father was waiting.

Steadying a tremble in his hand, Teàrlach made a swift, surgical movement. A gash opened across Erik's cheek; blood welled and dripped down as he growled and fought.

Job done, Teàrlach returned the dagger to his father, who wiped the blood on Erik's chest, opening another cut in the process, and returned it to its sheath. Murtholic nodded in satisfaction.

"Take him away," he ordered curtly, ignoring Erik's shouts as he was dragged to a nearby tent.

Teàrlach watched him go in thoughtful silence before returning to his silent vigil, and tried to shake the feeling that he was watching over two souls that night.

Around them, the wind howled on, relentless and cold.

A/N: I know this is a short intro, but I'm already working on the second chapter and should have it up soon!