~Theory: Jack and Sandy~
No one knew much about the history of Sanderson Mansnoozie. His past life was vague, but the only thing that is plausible is his relationship with Pitch Black.
Jack stared at the man made of sand as he sat across from Wander, drinking iced tea with a plate of shortbread cookies.
"I take it you're wondering about Sandy's past life?" Wander ignored Jack's look as she continued. "You're a very easy read Frost."
"Oh."
"As for your question, I do have a theory."
"Really?" This got the guardian's attention. "What kind of theory?"
"Have you ever heard of the story The Little Boy Who Cried 'Wolf'?"
"The Little Boy Who Cried 'Wolf'?" Jack repeated. "Is that the story where the boy lied too much and his sheep got eaten because no one believed him?"
"That's the one," The jester said as she sipped her tea. "My theory is—like the story—is that in the past; Sandy was once a boy that grew into a man who used his voice for pure wickedness. And when he pleaded to change his ways in the afterlife, the man was reborn as the Sandman; the price he paid was the use of his voice."
"…That doesn't sound too bad for a theory," The boy made of ice admitted, stirring his tea with a straw.
Wander smiled. "I'm glad you think so. Even Sandy likes the theory."
Sanderson then appeared in front of the two checking to see if everything is alright, and slightly smiled when he got his answer.
"Hey, Sandy?" Jack had asked. "What was your past life like?"
The only answer Jack got was a shrug which obviously translated to: "I'm not sure myself."
AN: Made for a friend who wanted to know my head-cannon for Sandy's past.