The sigil of House Harlaw is a silver scythe. The House Harlaw Reapers have taken that sigil and turned it into an actual weapon of war. Agricultural scythes make poor combat weapons, but the Reapers have adopted using long-handled axes with equally massive blades. These grisly instruments can mow down men in combat the way a regular scythe can mow down wheat in the field. House Greyjoy is putting them to use, clearing the battlefields of enemies.