Nitocris appears as a dark-skinned Pharaoh of ancient Egypt's Sixth Dynasty, ruling briefly in the 22nd century BC. Historical records debate her existence, suggesting her legend might stem from a misreading of Pharaoh Neitiqerty Siptah's name. Within the Fate universe, her legend follows Herodotus' account: she drowned the conspirators who murdered her brothers by flooding a sealed banquet chamber via a hidden conduit to the Nile. She then committed suicide without arranging her rebirth, deviating from traditional Pharaoh burial practices.

Her striking appearance features purple hair and elaborate Egyptian-inspired attire adorned with golden jewelry, including a prominent necklace. She wears distinctive Anubis-like ears, a design reflecting Japanese pop culture's kemonomimi trend, though her lore associates them with Horus. She wields a was-scepter, symbolizing royal authority and functioning as a mystical artifact.

Nitocris exhibits a dual nature: outwardly calm and wise during crises, yet internally fierce and prone to rash judgments. She possesses absolute self-awareness as a Pharaoh, viewing rulers as godlike entities. However, she becomes intimidated by legendary pharaohs like Ozymandias and Iskandar, often cowering or over-apologizing in their presence. Her vengeance against the conspirators was driven by both familial loyalty and upholding the Pharaoh's sanctity against defilement. Her deepest wish, sought through the Holy Grail, is confirmation that her brothers reside peacefully in the Egyptian afterlife ("Eternal Paradise").

In *Divine Realm of the Round Table: Camelot - Wandering; Agateram*, Nitocris serves as Ozymandias' ally, guarding the deserts surrounding his Egyptian territory within the Singularity. She aids the protagonists during their refuge in his kingdom, utilizing her abilities to protect the region.

As a Caster-class Servant, Nitocris specializes in instant-death mechanics and Arts-based Noble Phantasms. Her primary weapon is *Anpu Neb Ta Djeser* ("Nether Mirror's Precious Bible"), a mirror linked to the underworld that unleashes evil spirits. Upgraded via an Interlude Quest, it deals area-of-effect damage, reduces enemy critical hit rates, and has a chance to inflict instant death, particularly effective against low-level enemies. This ability draws inspiration from Brian Lumley's horror story *The Mirror of Nitocris*.

Her skills are:
- *Egyptian Magecraft* (later upgraded to *Works of the Underworld God*): Boosts instant-kill success and Arts performance while healing allies.
- *Rapid Words of Divine*: Charges her Noble Phantasm gauge.
- *Affection of the Sky God*: Grants herself a one-time revival (Guts status) and removes debuffs.
Her passives include *Territory Creation*, *Item Construction*, and *Divinity*, enhancing her magical capabilities.

An Assassin-class variant, tied to the god Medjed, appeared during a limited event. This version wears Medjed's iconic ghost-like garb and uses the Noble Phantasm *Sneferu Iteru Nile*. Both variants incorporate Medjed in attack animations, firing beams from his eyes.

Her relationships highlight her insecurities:
- She clarifies distinctions with the unrelated Babylonian Queen Nitocris to Gilgamesh and Darius III.
- She reveres Ozymandias as the "true Pharaoh," often stammering or seeking his approval.
- She imitates Cleopatra's fighting style but feels inadequate comparing their "sparkle".