Bastian readies an arrow into his bow.

Bastian was a male mouse and a member of the Mouse Guard. A Patrol Guard since 1138, Bastian's specialty was hunting predators. Unlike his fellow Guardmice who tended to avoid them unless a conflict was necessary, this orange-cloaked mouse felt that killing beasts known to eat mice and prevent their settling in the Mouse Territories made life better for all mouse-kind. His determination earned him a few battle scars, but none were serious enough to deter him.[1]

During the winter of 1152, Bastian - alongside Aubrey, Delvin and Sienna - was sent to the settlements of Elmwood, Whitepine, Dawnrock, Thistledown and Wildseed by Gwendolyn to gather supplies. He was also present at Celanawe's funeral later that season.[2] The following spring, Bastian and Delvin were sent by Gwendolyn to hunt down a snapping turtle attacking the settlement of Grasslake.[3]He peppered the turtle full of arrows so Delvin could slay it by slashing it across the throat.