Similar to her past self, she seems to deeply love Moroha, often wondering on how good it would be to go on a date with him since they aren't siblings in their current life, this is either genuine affection or obsession with him. However, she seems aware of Moroha still thinks of her as his little sister. In their past lives, she was Moroha's younger sister, until they were revived in the present time. After addressing each other as their names in the past, she happily and gleefully jumps at him, and starts calling him 'Nii-sama', which eventually becomes a habit.

Both first met in the academy's auditorium, following Mari's speech where she found him asleep and stared at him, only to wake him up by head-butting him which awoke him and knocked him over, tumbling a few chairs. Satsuki is a classmate and friend of Moroha. Last time I checked, a hit to the head always jogs the memory, but I'm not so sure for a memory that relates to your past life. (In the light novel, Shizuno initially feigns ignorance on knowing about Moroha's past life with her because she fears her family would retaliate against him if they found out that Moroha and Shizono were husband and wife. This is partly because she doesn't want to be vocal about their past lives like Satsuki and mostly because she wants Moroha to remember her on his own, as Shizuno wants him to atone for chaining her heart in this life and the last. To which Shizuno will deny answering his question. However, Moroha only recalls brief flashes of their past together and tends to question Shizuno on some of his visions. As of present, Shizuno's feelings for Moroha in the present are because the way he's acted for her sake, as well as that she remembers Moroha as Shu Saura. In a flashback of their past lives, she said that even if the whole world turned against him, she would always stay by his side, because she was his wife. The extent of their relationship at that point is unknown, but can be assumed they became close, in which, both would later rule over the Netherworld as husband and wife. Sometime later, where both were seemed to have escaped, or may have possibly occurred before, Moroha, as Shu Saura, using his magic, creates an object and hands it to her and smiles.

Although little is known about their past lives, both were seen to have met each other in some enslavement camp and ended up escaping at some point, with Shizuno, who, was the Witch of Netherworld, revealed that he was the one who had saved her. Moroha dislikes the way Shizuno's family treats her, as he described, being treated like a tool, something he made clear to Maya, who also agreed with him.

The romantic interest may be mutual, as seen in the last episode in which Moroha and Shizuno tried to kiss each other (with the kiss not being one sided from Shizuno), but they were interrupted by Satsuki. According to Maya, before he came along, Shizuno wasn't as happy, but after he arrived, she seemed to be happier around him, something that made Maya and Mari pleased. Regardless, both of them get along well and Moroha has shown to care for her well being, even though they had just met in the present time, with him even going all the way to save her and Satsuki from an attack from the Hydra that could've been fatal, after her and Satsuki's body were left partially petrified from the Hydra's previous breath attack, and when being scolded by her brother. Moroha is often the target of Shizuno's perverted antics, such as when she (purposely) shoves his head into her breasts, with each occasion making Satsuki jealous and leaving him uncomfortable with the situation, and from time to time, is randomly kissed by Shizuno as well. Their meeting started off by Moroha waking up a sleeping Shizuno (ironically, both of them fell asleep) who instantly kissed him after muttering Shu Saura, a past life of Moroha, who in the past, both were husband and wife. The two first met in the school's auditorium, following Mari's speech on what their role would be in the school. Shizuno is a classmate and friend of Moroha.

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