The creature was called an ent in the original Dungeons & Dragons, and its name was later changed to treant.

The elf appeared as a character class in the original Dungeons & Dragons Basic Set (1977).

The black (or gray) pudding first appeared in the original Dungeons & Dragons set (1974).

The abilities of the different character classes are based on the rules of the original Dungeons & Dragons game.

The efreet first appeared in the original Dungeons & Dragons "white box" set (1974).

The green slime first appeared in the original Dungeons & Dragons set (1974).

The core rules were available as three booklets in a boxed set (compare to the original Dungeons & Dragons format).

Humans first appeared as a player character race in the original 1974 Dungeons & Dragons boxed set.

Fighter was one of the three classes in the original Dungeons & Dragons game, then called "fighting man" (the other two were magic-user and cleric).

The dwarf is again a character class in the original Dungeons & Dragons Basic Set (1977).