The Raiden Shogun is a firm believer of what she believes to be eternity—a place in which everything is kept the same, regardless of what goes on. She is honorable in her conduct and is revered by the people of Inazuma.
The Raiden Shogun exists in two forms—Raiden Ei, her true identity, and the Shogun, a puppet created by Ei to act as the ruler of Inazuma in her stead while she meditates in the Plane of Euthymia. This puppet follows a set of directives programmed into her, which are extremely hard to modify even by Ei herself. The Shogun is cold and stern in personality, even callous at times; she is limited in emotional expression, has no likes and dislikes, and has no need for recreation. The Shogun thinks of herself as Ei's assistant, and does exactly as she wishes, no more and no less; she cannot act without Ei's direction, and if her usual functions are disabled, the Shogun becomes incapable of doing anything. Due to her limited protocols and Ei's initial indifference for anything other than her goal of eternity, the puppet can easily be manipulated by outside forces. For example, the Kujou Clan and the Fatui tricked her into initiating and maintaining the Vision Hunt Decree.
While Ei has a more stern demeanor than the average person, she is notably more emotive and sociable than the Shogun. Unlike the Shogun, Ei has preferences, such as a love for sweets and her passion in martial arts. Due to her
dedication to eternity, Ei is wary of the idea of change. However, she shows curiosity rather than disdain when it comes to new things, such as the appearance of the Traveler[4] and the customs of the modern world. Due to having lost many of her loved ones over the centuries, Ei is driven by a fear of further loss, wanting to preserve Inazuma for all eternity. To this end, she sealed herself in the Plane of Euthymia to keep herself from the effects of erosion, while she created the puppet Shogun to be immune to the decay of the physical body. While in the Plane of Euthymia, Ei was indifferent to anything that did not affect her pursuit of eternity and had a low opinion of human ambition due to said ambition leading to loss and suffering, thus making it incompatible with eternity. Even in the Plane of Euthymia, however, she could not truly escape loneliness, as she was happy to see her friend Yae Miko again, and she genuinely enjoys the Traveler and Paimon's company.
Ei has a weakness against desserts and sweet things. Her view is that desserts can't pose any serious obstacle to her pursuit of Eternity to the extent that in any case of cavities, she could just replace her tooth. Miko and Venti also mentioned about her fondness against desserts, with the Anemo Archon even suggesting that the Traveler bring her desserts to exploit the said vulnerability. During her story quest, when asked by Traveler, Ei explained that since humans enjoyed desserts, she should enjoy it as well. Ei also has an aversion to cooking, saying that she can do anything but that.
In spite of her flawed actions, Ei truly loves Inazuma as her sister did and just wants to protect it and her people for all eternity. After she is convinced that her actions were wrong, Ei shows remorse and is willing to change her perspective regarding eternity and become a better ruler for her people.
The Raiden Shogun's physical appearance is that of an adult woman, with long braided violet hair behind her back, and on the right side of her head is attached a hairpin with pale violet flowers resembling morning glories and a fan-shaped piece; the latter part belonged to Ei's twin sister, Raiden Makoto. Her eyes are purple and she has a beauty mark below her right eye. She wears a small crimson ribbon on her neck as a choker and a dark-colored bodysuit underneath her kimono. The sleeves of her bodysuit completely cover her arms and are looped over her middle fingers with golden rings to partly cover her palms and the top of her hands, and her nails are painted purple. Her kimono has an assortment of patterns in different shades of purple and crimson, along with a badge bearing the Mitsudomoe emblem of Inazuma tied to the front of her clothing below her right breast and a more elaborate emblem on a pauldron on her left shoulder. On the back of her outfit, she wears a crimson bow with tassels. She wears dark purple thigh-high stockings with small diamond openings at the top and high-heeled sandals; the one on the right is adorned with two of the same violet flowers on her hairpin.