Kurumi Saiki is the mother of the protagonist Kusuo Saiki and his older brother Kusuke, and the wife of Kuniharu Saiki. She is a gentle and warmhearted housewife who provides the emotional anchor for the Saiki family. Despite being in her late thirties, she maintains a remarkably youthful appearance, with short black hair and kind, black eyes.

Her personality is defined by an unwavering kindness and a trusting nature that borders on naivete. She never doubts others, which sometimes makes her an easy target for pushy sales tactics, but it also creates a home environment free of suspicion. According to Kusuo, it is precisely this quality that kept him from using his immensely powerful psychic abilities for selfish or harmful purposes, as he could never bear to disappoint her.

Kurumi’s primary motivation is the happiness and well-being of her family. She is overjoyed whenever Kusuo makes friends or shows any sign of a normal social life, and she dotes on her husband despite his frequent childish antics. Her love is unconditional and serves as a quiet but constant moral compass for her children.

Within the story, Kurumi fills a supporting but essential role. She is not directly involved in the supernatural chaos that surrounds Kusuo, but her presence is deeply felt through his internal monologues, where he often reflects on how her influence shaped his character. She appears mainly in domestic scenes, but each appearance reinforces her status as the heart of the household.

Her relationships are central to her characterization. With Kusuo, she is a loving, permissive mother who trusts him completely; Kusuo in turn respects her deeply and strives to protect her from the truth of his powers. With Kuniharu, she is a devoted wife who appears unfazed by his eccentricities, maintaining a cheerful partnership that models a stable home. With her elder son Kusuke, she shows the same unconditional support, even though he is often absent pursuing his own genius-level projects. She is also allergic to cats, a small detail that sometimes leads to comedic moments.

Kurumi does not undergo significant personal development over the course of the series, as her character is already fully formed as a virtuous and steady adult. Instead, she functions as a consistent positive force, reminding both the characters around her and the audience that genuine kindness and trust can have a profound, quiet impact. She possesses no special abilities beyond ordinary human compassion, yet that compassion is portrayed as a power in its own right, capable of guiding a child with the potential to reshape the world.