Elymis was a quiet, male mouse and a member of the Guard. He was usually found in Sienna's patrol. Being a skilled scout, Elymis often went ahead of his party, moving silently and observing all signs, sounds and smells which may have helped guide their group away - or in some cases - towards predators and danger. A friend to Midnight before his disastrous plan to take over the Guard, Elymis became distrustful of others; and has since seen the Guard as vulnerable - even from just a single mouse.
During the winter of 1152, Elymis - alongside Annika, Cerise and Sela - were sent to the settlements of Darkwater, Lonepine, Burl, Sandmason and Mapleharbour to gather supplies. Elymis was present at Celanawe's funeral, later that season.