Her name "Makki" is actually not her real name, merely a fake identity. Her Servant Tsuda refers to her as Lady Yukika (由紀香殿, Yukika-dono?). She is a survivor of the disastrous Fuyuki Holy Grail War, and is hinted as being an alternative, older version of Yukika Saegusa. Her partnership with Tsuda mirrors the friendship between Yukika and Kojirou in other timelines.
Makki has been working with Chitose Manazuru since the formation of Mosaic City. Years ago Nami and Mr. Utsumi invited her to enter Mosaic City when she was wandering the uninhabitable wasteland outside its borders.
As a part of the Nightwatch, she is the the senpai to Erice Utsumi. Makki used to be working alone conducting expeditions outside Mosaic City but recently returned to help Caren Himuro with issues surrounding the Command Spell Hunter incident. Despite the state of the world outside Mosaic City, Makki has an ability to "avoid dangers" and survive Fuyuki for long periods. Since her return, she inherited the Shroud of Magdalene, a relic passed down to her by Caren Fujimura after her death and has been the user since.
A hardened-looking adult woman whose three-piece men's business suit fits her form perfectly. If you subtracted the height of her boots, she probably wouldn’t be much taller than Erice. While looking at around her twenties, she's actually a whole lot older. Erice assumes her age to be around 40 to 50 years old. She looks young due to "MethuselahWP treatment".
Makki is rude and crass. Makki was seen to be uncaring and stoic at first, but further interactions with Erice softened her up and she starts warming up to both Erice and Voyager, but still however reluctant to speak anything that seems to involve Erice and her actual identity. Makki was also knowledgeable that she immediately found out that Voyager cannot spiritualize himself due to Erice's ability and nature.
She also knows a lot about Erice and her family, especially her parents, which she owed them a favor for letting her into Mosaic City when she was still outside wandering around the ruins. She was also highly aware of Erice and her nature but refused to let her know everything, often cut her short.
Makki resents Caren Himuro for recklessly working her while wearing a maid dress.
Shinjuku the Nostalgic City
Makki arrests Kuchime for giving her false information about the Command Spell Hunter incident. However he is shortly released as there is not enough evidence to connect him to the incident, as well as him having an alibi for Nzambi's attack on the Grail Tournament, having been in Shinjuku at the time.
She was able to survive in the hell outside Mosaic City caused by the war.
As a member of the Nightwatch, Makki possesses an authority give to her by the Caren Series called Higher Communications Authority. This gives her the ability to jam or intercept any citizen of Mosaic City's communications. By making a chopping motion with her middle and index fingers, Makki was able to instantly cut Karin's phone connection, preventing her from making a call.