A/N: This one’s a short drabble but I have many more CD AUs! Also, C-ta’s a year younger than D-ne here.
"Hmm?" C-ta looked up from his book to look at his half-sister. She was clutching her favorite doll and she was rubbing her eyes sleepily. C-ta sighed and placed down his book on his desk. "What’s wrong, D-ne?" He asked, motioning D-ne to come closer. She walked towards him, wrapping her arms around his waist. "…I’m scared."
C-ta ran his fingers down D-ne’s hair, trying to soothe her. “Did you had another bad dream again?” He asked, pulling her close. He felt D-ne bury her face on his shoulder, mumbling something about a demon or something.
"Ssshh… Don’t cry… I’m here."
C-ta scooted a little bit to the side of his bed to make some space for D-ne. “Here, you can sleep next to me.” D-ne smiled and she immediately climbed into C-ta’s bed. She snuggled next to him. C-ta smiled and wrapped an arm around D-ne’s waist. “Goodnight, D-ne.” He kissed her forehead tenderly.
"Goodnight, onii-chan…" After mumbling a few more incoherent words, D-ne fell asleep. C-ta stared at her lovingly, his other hand caressing her face. "…Oh, D-ne…" He grinned. "I won’t let anyone get you… You’re mine…"