There's an awkward silence in the compartment as the girl with the headphones and the youngest redhead boy sat across Harry. The girl looks up from her phone, and elbowed the boy.

"OW! Um, so..." He glanced around, "I'm Ron Weasley, and this is Hirutasu... She doesn't talk." A glare. "A lot."

"it's Mayumi."

Mayumi Hirutasu stated it so bluntly it's impressive, and Ron Weasley gave her a look of betrayal.