Spiders in the Cloakwood

When you enter the second part of the cloakwood forest, there will be peasant by the name of ? looking for his brother Shelak. He and Shelak went to the Cloakwood Forest with a sword made to kill spider for the killing of spiders, Spider's Bane, to find the source of the huge spiders and destroy it for once and for alland hoping they would become the heroes of Cloakwood Forest if they succeeded. However his brother went searching for the source of the spiders ten days ago and didn't return and the group of adventurers is asked to find him.