Only a few video games had real characters already in the year 1984, this list will grow very slowly.

Noteable is the debut as Hulk as one of the first Marvel characters in a video game as part of the Questprobe games.

 

Video Game Characters first seen in 1984 featured on Game-Art-HQ

Gilgamesh (Tower of Druaga)

Gilgamesh

Hulk

Hulk