Disclaimer: I don't own any of it. All hail to Moffat, Gatiss and Doyle.
Summary: When he was a child, Mycroft decided to be the perfect host to his brother, based on Ancient Greek customs. Over the years, both he and Sherlock evaluate their relationship by comparing themselves to mythological hero's, while trying to keep each other safe.
Filia – Chapter 1
Mycroft was many things to many people. To his parents, he was their eleven-year-old genius. Full of promise, but also a stranger to both of them. There was no warmth in their relationship, no understanding. Passive appreciation or replaced ambition, perhaps, but no love. To his classmates, he was an easy target. It was embarrassing for Mycroft to admit. He was smarter than all of them, could manipulate them without any effort, yet their fists were inescapable. It wasn't just physical violence, though. The sniggers when he raised his hand in class had made him nervous to speak up. And when the teacher had given him a turn and when the giggling had started, the words had stuck in his mouth and he'd officially become a stutterer. It only happened at school, never at home, so Mycroft kept it a secret. To his teachers, however, he'd subsequently started to be a figure of pity, though even they were distanced by his knowledge and formal manners. They never reached out to him.
To his four-year-old brother Sherlock, he was the world.
But eleven was the age when the adulation of a younger sibling was no longer enough to create an identity strong enough to form a protective shield against the world. Mycroft had begun to carefully build his own character. Intelligence and knowledge were a part of him, but he wanted to be more than that. He wanted to have a sense of honour, a sense of pride, a sense of virtus that would ward off any humiliation.
Mycroft was top of his class in all his subjects, but in Greek and Latin he'd always done exceptionally well, even for his own standards. And when it came to honour, there was no better source to turn to than antiquity. It was ten o'clock in the evening and he was in bed, curled up with a small reading light to keep his parents from knowing he was still awake. He was reading a rather extraordinary passage on the custom of receiving guests in Ancient Greece when his studies were interrupted by the door to his room slowly opening.
Mycroft turned his head to look. Sherlock, one fist curled around the hem of his shirt, the other held at his side. Bare feet, lip trembling slightly. Nightmare, Mycroft concluded within half a second.
"Sherlock …" he began and was about to rebuke his brother for leaving his bed when he remembered that guests in Ancient Greece were welcomed regardless of their past transgressions. They were invited in, fed, clothed and the host would never even ask the identity and purpose of their visitors until days after their arrival. If honour was something he aspired, he might as well start tonight. "Come in."
A smile lighted Sherlock's face for a moment. He closed the door and padded towards Mycroft's bed, making his brother wince as he crawled underneath the covers and warmed his cold feet against his Mycroft's warm legs. Mycroft put away his book as Sherlock snuggled up to him.
"I wasn't scared." Sherlock muttered defiantly into Mycroft's nightshirt, his tiny fingers now curled around his brother's clothes. "'m not a baby."
"Of course you're not."
"Want a story."
"Do you, now?" Mycroft asked him, amused. "And what's the magic word?"
A cold foot kicked his shin, but not as hard as Sherlock would've done if he'd actually been angry. Or properly awake. "Story."
Mycroft sighed. They could go on like this for hours. Sherlock had clearly already decided that politeness was never going to be part of his character. "Fine. Did I ever tell you about Castor and Pollux, or Polydeices, as the Greeks called him?"
"No, not the stars. At least, no yet. Two brothers, who were born in Sparta, many, many years ago."
"Which am I?"
"Castor or Pollux. Which one is me?" An insistent finger poked at Mycroft's ribs.
"Well, I suppose," Mycroft considered carefully, "if you were to be one of them, you'd be Pollux. He was the son of Zeus, the mightiest of all the gods, and therefore immortal. That means he could never die. But his brother Castor had a mortal man as father. And one day, after the brothers were betrayed by their enemies, Castor was hurt with a spear and was close to dying. But Pollux asked his father to help them and Zeus made an agreement with the two brothers. They could share death and life together. One day, they'd have to stay with Hades, the god who lived in the underworld with the shades of the dead, but the other, they'd be allowed to go with Zeus and the other gods to Olympos, the high mountain where they lived. That's how Castor and Pollux got to be together forever."
He looked down at his brother to find Sherlock sleeping soundlessly at his side. Lowering his voice, Mycroft whispered: "Would you be willing to do that for me, Sher? Bargain with the most powerful of the gods to save me? I'd do it for you. Without a second thought. But that's not the same thing. I wouldn't allow you to do it for me. You should always be the one with the gods in the sky. You're much too light to be down in the depths with me."
He threaded his fingers through Sherlock's soft curls and the sleeping boy drew a little closer to him.
"Son of the gods," Mycroft breathed. "That'd definitely be you."