Final answer:
Niflheim is the Norse realm that serves as an afterlife.
Step-by-step explanation:
The Norse realm that serves as an afterlife is Niflheim. In Norse mythology, Niflheim is described as a cold and misty realm located in the northern part of the world. It is associated with darkness, ice, and a frozen landscape. When a person dies, their soul could end up in Niflheim if they did not die in battle and earn a place in Valhalla, which is another realm in Norse mythology.
Learn more about Norse mythology and afterlife