Boudica is a Rider-class Servant from Second Singularity, Septem.

Fate/Grand Order: Mortalis:Stella:
Boudica is one of Nero’s generals against the United Roman Empire. The goal of her expedition is to retake Gaul. Appears in chapter 13 onwards.

Fate/Grand Order: Epic of Remnant IV - Salem:
She briefly appears in chapter 17: she talks with Ushiwakamaru, Mordred and Emiya in the Chaldea dining room.