Big Ash is a Shawnee contact of Nick Hawley. He and his fellow Shawnee run a motorcycle repair shop. Ash was displeased with Hawley for selling off the tribal mask, as Hawley dishonored his agreement to keep the mask.
Hawley initially assumed that Ichabod Crane was too socially awkward to communicate with Big Ash. But Crane's mention of Squire Boone became the key for Big Ash to agree to help them find a Wendigo cure for Joe Corbin.