Agnes MacBean is the Scottish engineer who owns the train the Frye twins use as their moving hideout. She comes with it after the Whitechapel gang war, keeps it running and improving, and sets up the Train Hideout side stories.
Her father Mungo worked the rail yards of the new Garnkirk and Glasgow line. When his health failed in 1834, Agnes took his place on the locomotive and his identity with it. Around 1836 her employers found out she was a woman and transferred her to Starrick Industries in London as punishment.
After the twins beat Kaylock in Gang War: Whitechapel, the train passes to them and Agnes with it. She urges them to spend their money on the city, and over time adds upgrades to the train that serves as their home and headquarters.
In Stalk the Stalker she asks Evie to help her catch the young man following her on her errands; he turns out to be Nigel Bumble, who wants to join the Rooks, and she takes him on as a cleaner. She also keeps the twins informed of Rook news, as when Nigel is arrested, and patches up the driver's apprentice Bob after Jacob brings him back injured.
Nigel Bumble
Nigel Bumble is the eager, accident-prone young Rook at the heart of the Train Hideout stories. He follows Agnes around London until she lets him join, gets arrested after a night out, and thanks the twins by stealing a Gatling gun for the train.
Duleep Singh
Duleep Singh, the last Maharaja of the Sikh Empire, is Henry Green's great-uncle. He helps Evie find the Buckingham Palace plans in Family Politics, and is the central figure of The Last Maharaja missions, where the twins help him fight the British India Company.
Henry Green
Henry Green is the head of the Assassins in London when the Frye twins arrive in Assassin's Creed Syndicate. He runs a curiosity shop in Whitechapel that doubles as the Brotherhood's bureau, introduces Jacob and Evie to their key allies and works alongside Evie on the search for the Shroud of Eden. His birth name is Jayadeep Mir.
Rexford Kaylock
Rexford Kaylock is the Blighter leader of Whitechapel, the first borough the Frye twins fight for in Assassin's Creed Syndicate. He is the target of Gang War: Whitechapel in Sequence 3, and beating him hands the twins the train that becomes their hideout.