Kalrag is a giant spider encountered during Underground Pass and only needs to be fought during the quest, although players can kill it afterward. It must be slain in order to soak a player's doll of Iban with Iban's blood, thus progressing the quest.
The blessed spiders nearby will attack you with melee after you kill Kalrag.
It is recommended for the player to wear full rune or above so that the blessed spiders deal very little damage. It is possible to safe-spot Kalrag as she uses melee, so you could equip the bow and arrows you brought to pass the bridge in order to attack from a distance. After Kalrag is slain it is advised to leave immediately to avoid taking too much damage from the blessed spiders.