Manamusume

Manamusume (愛娘 Manamusume) or “Daughter Dearest” in English, alias Grete, is one of the main protagonists introduced in Spy Classroom series.

Appearance
“A girl with her characteristic red-haired bob cut. She held a long, slender body, [...] charming body, no excessive fat to be seen, and her calm and soothing voice, she gave off a fleeting, almost feeble impression. Just like a delicate glass framework, she could break if one used a rough hand against her”