Ekaterina originates as the anthropomorphized incarnation of an antique pistol once prized by Tsarina Ekaterina the 2nd of Russia. Crafted from ivory and gold and adorned with intricate floral and rose patterns, this firearm embodies luxury and artistic craftsmanship reflective of the Tsarina's patronage of the arts. In human form, Ekaterina manifests as a petite figure standing 145 cm tall with a slender build, characterized by fair skin, light aqua-blue curly hair styled in an elaborate updo with straight bangs and short sidelocks, and dull purple eyes. Ekaterina frequently displays a small, doll-like smile.

Her personality centers around elegance and refinement. She expresses enjoyment of dresses, jewelry, stuffed toys, poetry, and fairy tales. Ekaterina associates increased power with enhanced cuteness and often remarks on the appeal of fashionable attire. Within the narrative, she collaborates with Aleksandr, another anthropomorphized firearm from the Romanov era, engaging in lighthearted references to his perceived shortcomings. In game mechanics, Ekaterina is designated a 2★ rarity unit with initial attack statistics of 240x2, evasion of 300, and accuracy of 300.

Character stickers featuring Ekaterina's artwork have been commercially released.