A nod to Rorschach's Blot, another legend for the fabled Mr. Black perhaps? and thanks to Shadowfemale20 for the prompt
"Dada, why do we have to sit in the circle with the Siren ladies every year?" At 6 years old, sitting on the beach at the end of the day, Teddy finally asked the question he'd wondered about for years.
"Did we never explain it to you Ted?" He shook his head. "Well, I need to tell you two stories. Once, a long, long time ago, when Hogwarts was still new, a man, let's call him Mr. Black, was sailing home, when he noticed a lady lying on a bit of wood, very hurt, because she'd been in a shipwreck. He got her onto his ship, and healed her up, and cared for her until she woke up. What he didn't know, was she was a Siren."
"Like Kailani?" Teddy excitedly asked.
"Sort of Ted, more like Lady Mairian." Harry agreed. "So when she woke up, she gave Mr. Black a gift. A reward. Not an ordinary reward like money, what she gave him was much more special. She made it so he and all his family would have a home on the sea. This would be a kingly gift for anyone, but for Mr. Black it was extra special, for he and his family made their money on the sea, trading and ferrying and other things. What they didn't know, was later on, his descendants would be called to the sea, they would feel restless on land, unhappy until they were back on the water with the wind in their hair and a deck under their feet. The problem was, sometimes they didn't come back, and someone was always left behind, missing the person called away to the sea. So Mr. Black's family left the sea, and moved inland, so that the sons and daughters could grow up and have wives and husbands and sons and daughters before they went to sea. And so the Black family named the gift the Black's Call. The next story, not quite so long ago, involves a man and a woman, who left England when they were 12. The girl was a Governor's daughter, and was sailing with her father on a Navy ship to Jamaica, singing the pirate songs her mother had taught her before she died, when, just like Mr. Black, she saw someone in the water who'd been shipwrecked. The same as Mr. Black, they brought him aboard and cared for him. Before the ship's doctor took him, she found he had a medallion. A pirate medallion. She took and hid it to protect him, because in those days, pirates were hanged. 8 years later, when they were grown, the Governor's daughter and the boy who'd become a blacksmith, fell in love and had several adventures, becoming pirates themselves, getting married, and eventually, she became the Pirate King, and he became the new captain of the Flying Dutchman, the ship that takes all those who die at sea to the other side. Again, there was a problem Ted, for the captain was immortal and could only have one day ashore every 10 years, and she couldn't sail with him, because she was still alive. So although they were sad, they spent their one day together, then just before sunset, he had to leave, back to his ship to ferry the dead. She stood on the shore and watched, beginning her ten-year wait. Ten years later, she stood on another shore with their son, and waited for the green flash that would signal his return from the other side." Just as Harry finished speaking, a green flash lit the sky. The two looked at each other with comically wide eyes, then both immediately began yelling for Andromeda and George as they raced to the house to get the Director through the Floo with the two sea chests, the end of the story all but forgotten.