The Killing Quest in the Name of ... is actually a collection of quests grouped around the same name, as well as Tibia Tales and The Ultimate Challenges. All are intended to kill certain creatures (Killing Tasks) for rewards, and some tasks may be repeated several times..

To choose a task you need to say hi > task > name task

To report a task you need to say hi > report > name task

To cancel a task you need to say hi > cancel > name task

You can repeat the task 4 times and take 2 tasks at the same time.