Final answer:
The common element of science fiction that is missing in "Nethergrave" is the use of futuristic technology or concepts.
Step-by-step explanation:
The common element of science fiction that is missing in "Nethergrave" is the use of futuristic technology or concepts. Science fiction literature typically revolves around science and technology that does not yet exist, such as aliens, life on other planets, parallel worlds, or time travel. However, in "Nethergrave", the story focuses on virtual reality and its consequences, which is a concept that exists in the present time.