Thomas was born in Wolverhampton in 1894, the son of James and Sarah Ann Killin. In 1911 he was living with his parents at 244 Newhampton Road, together with sisters Bessie Goldie, Janet, Madeline Grace and Phyllis Mary, and brothers Harry and Allan Montgomerie. Thomas was a clerk with the London and North Western Railway.
Thomas enlisted with the Royal Fusiliers (number PS/6915), first entering the war on 14 November 1915. According to his medal card, he died of wounds on 11 November 1916, but I have been unable to find him on the Commonwealth War Graves Commission site, even with variations on the spelling of his surname. His death was registered in Lambeth in December 1916, and his name was included in a list of men who died in the Express & Star on 18 November 1916. He may be the “C. Killin” listed on the memorial of the Wolverhampton Higher Grade School.