"Haruka is a significant character in the Japanese manga ""Demon King, your big brother wants you home for dinner."" The manga follows the life of a young girl named Ningyō, who discovers that she is the reincarnated daughter of the demon king. Haruka plays an essential role in Ningyō's journey, and her character is developed through the course of the story.

Haruka is the adopted sister of Ningyō and her brother, the demon king. She was found as a baby by the demon king and raised alongside Ningyō and her brother. Haruka plays a motherly role in the group and acts as a caretaker for the younger siblings.

Haruka is a kind and gentle soul who cares deeply for her family. She is also incredibly smart and resourceful, often helping Ningyō and her brother with their problems. Haruka is a skilled healer and knows how to use magic to help those in need.

Despite her kind nature, Haruka has a fierce and protective side. She is willing to do whatever it takes to protect her family, even if it means facing off against powerful foes. Her bravery and determination are admirable, and she serves as an inspiration to everyone around her.

Haruka's backstory is shrouded in mystery, as she has no memory of her past. However, she is determined to uncover the secrets of her past and discover who she truly is. Her journey towards self-discovery is a compelling subplot of the manga and adds depth to her character.

Overall, Haruka is a vital character in ""Demon King, your big brother wants you home for dinner."" Her kind nature, intelligence, and bravery make her a beloved member of the cast. Her journey towards self-discovery adds another layer of complexity to her character, making her a fascinating and compelling character to follow throughout the story."