|Probably my all-time favorite illustration of a goblin
The most iconic adversaries for a party of adventurers exploring the first levels of a megadungeon are kobolds, goblins, and orcs. While D&D has always differentiated these as three different types of creatures, an examination of etymology and Tolkien suggest that they are three different names for the same type of creature. The word kobold is a German form of the Latin gobalus both of which come from the Greek κόβαλος. In turn, Tolkien himself suggested that orc and goblin are two different names for the same creature (having used goblin in earlier works for what would later be called orcs).
If one looks at the meaning of κόβαλος and orcneas (a plural of orc used in Beowulf), there is a suggestion that kobolds, goblins, and orcs are all human.
A κόβαλος was an impudent rogue and the adjective κόβαλα had the connotation of knavish trickery. Later it was associated with goblins invoked by rogues. Orcneas is often translated as evil spirit and literally means underworld corpse. It could be argued, then, that kobolds, goblins, and orcs are all varieties of humans who have willingly aligned themselves with Baalzebub, Asmodeus, etc. and have either been transformed or are possessed by demonic powers.
This understanding of these creatures is actually hinted at in the 1e MM:
Orcs dwell in places where sun-light is dim or non-existent, for they hate the light.
This mirrors John’s use of the Light/Dark motif is his Gospel:
And this is the judgment: the light has come into the world, and people loved the darkness rather than the light because their works were evil. — 3:19
Intriguingly, the word translated here as judgement is κρίσις, the root of the English word crisis. While the Greek does have a connotation of trial and judgement, it can also mean decision or choice.
The reasons behind this choice can be gleaned from the polemics of Ezekiel 28 where the King of Tyre is condemned to the pit (v. 8) and is turned to ashes on the earth (v. 18) because he claimed, “I am a god, I sit in the seat of the gods” (v. 2). While it could be claimed that this is directed at an earthly king, the Lament over the King of Tyre in verses 12-19 call him a guardian cherub who was placed on the holy mountain (v. 14, 16). In other words, the King of Tyre is seen as a Baal.
In the Baal Cycle, Baal kills Prince Yam-Nahar and takes his throne as the King of the Gods. Yet, despite (or more accurately because of) his victory, Baal fears Mot, the personification of death:
But take care, divine servants: Do not get too close to Divine Mot, lest he take you like a lamb in his mouth, like a kid, you be crushed in the chasm of his throat. The Divine Lamp, Shapsh, is red; the heavens are weak in the hands of the Beloved, Divine Mot. From across a thousand acres, a myriad of hectares, at the feet of Mot bow down and fall, you shall prostrate yourselves and honor him.
Despite the apparent victory and enthronement of Baal, he has no real power because even he cannot approach the land of the dead without being consumed. He killed in order to gain the throne, which means someone else could do the same to him. Like other hero myths from around the world, the Baal Cycle sees Baal forced to go into the underworld (Mot kills him) and then returning with knowledge that allows him to subjugate death.
Thus, at the heart of the Baal Cycle and the other pagan myths that follow the same pattern, is a desire to overcome death using one’s own power — without God. The polemic found in Ezekiel 28 proclaims the folly of this endeavor and warns:
[you will be] thrust down into the pit, and you shall die the death of the slain in the heart of the seas. (v. 8)Thus, from a Scriptural view, kobolds, goblins and orcs could be seen as what remain of those who align themselves with Baal and attempt to cheat death. What remains of them are underworld corpses, possessed of evil spirits trying to steal from humanity what once was theirs before they turned their back on the Light and embraced Darkness. It is their former humanity, and the temptation for other humans to cheat death without God, that see them occupying those levels of the megadungeon closest to the surface.