A box weapon is eternal. It can last forever as long as its master takes proper care of it. Throughout time a box weapon would naturally become close to its master. Hibari Kyoya's weapon, Roll, is no exception.
"Tell us, Roll, what you love about your master? He seems so scary," Natsu shook in fear just thinking about him. Roll softly smiled.
"He's a bit rough on the outside, but when it's just Hibird, him, and I, he's shows kindness like no other. He makes me feel safe when it should be me that protects him. He's strong and dependable. There's so much about my master that I love," Roll told him shyly. Roll couldn't deny that she indeed loved her the young Vongola Cloud Guardian. Despite the fact that box weapons might be everlasting, humans are not.
As time went by, Roll noticed how her master grew older as she stayed the same. An ache grew in her heart. She knew as everyone else that he'd die eventually. Just like Hibird who died soon after the Millefiore incident.
"Roll," an old Hibari opened his box weapon. She came out and lied next to him on his bed. He smiled and petted her. "I don't have much time left."
"Kyuu…. Hibari-sama….," she frowned as tears began to form in her eyes.
"I won't be able to take care of you anymore so I must pass you onto the next Vongola Cloud Guardian," he explained to her.
"Kyuu! Hibari-sama! No! Please don't make me!" She protested. She didn't want anyone else but Hibari as her master. The aged Hibari frowned and sighed.
"He'll take care of you for sure…." His voice trailed off, and soon enough he was gone from Roll's life forever.
"Kyuu! Kyuu! Hibari-sama! Hibari-sama!" She cried until she was forced back into her box. "Hibari-sama…"