Giles Lefton (formally Aegidius Lefton) comes from a posh and well-educated family with multiple estates across England. A talented student, he did well in Fox House at Schola and then went on to university to study Mathematics (his interests span both magical and non-magical applications, but he has a particular interest in cryptography and hidden patterns.) He volunteered for the War effort before conscription started, and was serving as an officer in the trenches in Flanders in 1915 when one of the early attacks by a new magical gas flooded the trench. He was able to get a number of his men to safety, but became blind due to the gas effects over the next few days. He spent time first at St Dunstan's, established to help veterans who had been blinded during the War (a real place, now Blind Veterans UK), before spending some time at a smaller home called The Refuge, to learn some supplemental magical skills. At that point, he took up residence in one of his family's homes in Trellech with his cousin Philip Vale as an assistant and secretary, and resumed his position as a professor at Oxford, splitting his time between Trellech and Oxford. There's a long history of accomplished blind mathematicians and academics he's glad to draw on.
Blindness notesBlindness due to gas attacks often took a few days to become apparent. In Giles' case, the effects are similar to mustard gas, but with less in the way of chemical burning to the lungs and skin. As with many people who are blind, he has limited vision - rough shapes with his left in the right lighting. He usually wears round shaded glasses, both to protect him from bright light (which he finds painful) and to avoid unpleasant comments from others. Giles is largely independent in spaces he knows well. He uses a number of techniques used or developed around this time: braille writing, an abacus for mathematics, a typewriter and braille writer. He also uses a few magical tools that are similar to modern technology tools, effectively a navigation beacon that allows him to orient himself in a room more quickly. A secretary or assistant to help with printed material goes a long way. (The long white cane and guide dog methods of independent travel are still works in progress in the 1920s, but as mentioned in Best Foot Forward, Giles gets a guide dog early in their introduction in the UK, named Madeline.)
Wards of the Roses
In Wards of the Roses, Giles needs an assistant to handle tasks that need sight. After considering two other candidates, he realises Richard Edgarton is recommending Kate without coming out and saying so. While they take a bit to get used to each other, they establish a good working relationship shortly before they and up trapped in the basement of Mannering House and have to rely on each other to get out. (The fact Giles is used to navigating spaces without sight and has learned the skills that make you a lot less likely to smack your head into something are a great help, actually.)
Country Manners takes place after their engagement (late summer 1921) and before their marriage in early 1922. There is an obligatory family visit to Giles' family, none of whom appear to approve of Kate. She is fortified by help from friends (including Alysoun Edgarton). Fortunately for their sanity, they stumble across a small but necessary mystery to be solved. This novella also explains how Kate came into possession of the Pleasing Token she wears in Outcrossing. By this point, Kate has found Giles a valet, a former dresser from the theatre, who's a great fit for what Giles needs a hand with.
On The Bias
Kate and Giles are guests at the costume party Geoffrey Carillon throws at the end of On The Bias. (Giles is dressed as Nicholas Saunderson, a blind mathematician of the 18th century, and Kate is dressed to match him as his wife.) When Carillon is attacked, Kate and Richard Edgarton are quick to take charge of the situation while Alysoun Edgarton and Giles Lefton go to consult for specific help.
(Click on the title above to learn more about Giles's role in that book.)