Abaddon, from Hebrew אבדון (Avaddon) meaning "destruction", is the Keeper of the Key to the Abyss and Guardian Power of the Soulstone. Precisely, he is witness and vigil of the Soulstone; he does not defend nor protect for the Stone needs not such. Furthermore, only Abaddon possesses the power to grant passage through the Gates of Sheol.
When Adam encounters him, Abaddon is kept prisoner by Claude Florentine, bound by a red light inside the Halls of Doppelgangis. He doesn't fight against it because internment was prophesised for his soul. The light and Florentine are merely variables whereas internment is the constant, his fate. Hence he cannot be freed and has to remain within the light if Prophecy is to be fulfilled. His only concern now is Florentine's humiliation which is why he urges Adam to fulfill the Prophecy and restore the Balance.
In Biblical references, "Abaddon" comes to mean "place of destruction", or the realm of the dead, and is associated with Sheol. Abaddon is also one of the compartments of Ghenna. By extension, it can mean an underworld abode of lost souls, or hell. In some legends, it is identified as a realm where the damned lie in fire and snow, one of the places in Hell that Moses visited.
In the Book of Revelation, Abaddon is personified as "Angel of the Abyss" or "angel of the bottomless pit", respectively rendered in Greek as Apollyon, who is bound until he is loosed in the end times to release havoc on the earth. In a later passage, then, he is identified as the one angel who is able to seize and bind the Devil.
Abaddon: Travellers, where are you bound? I am Abaddon, Keeper of the Key to the Abyss. Know that I have dominion here. Know that only I have the power to grant passage through the Gates of Sheol. Adam: Can you tell us anything about the worlds beyond the Gate? Abaddon: I can tell you nothing. You must enter, there is no other way. Adam: Perhaps you could tell us something about this place in which we stand. Abaddon: This grove in which you stand is hallowed ground. It is against all Law to spill blood within this sanctum. Adam: We come in search of the Soulstone. Abaddon: Know then that the arch will take you there. Step forward. Enter.
Adam: Has anyone passed through the Gate recently? We have enemies who stand against us. Abaddon: There have been three. Adam: Who were they? Abaddon: Names are of no importance. Adam: Oh come on! Abaddon: Their Signatures were Lies, Hope and Abandon. Adam: Signatures? Rebecca: Every Soul has a Signature, yet few can perceive them. The Liar must be Belial. Hope, I think, must be Hawk. Adam: And Abandon must be Gaul. Rebecca: Ready? Adam: Ready as I'll ever be. We are ready to pass through the Gate to the three worlds beyond. Abaddon: Go unto the realms of beyond! Eternity beckons.
Abaddon: Are you here to finish what you started Florentine? My captivity is fruitless Florentine. The Prophecy will be fulfilled. Another will come to take my place. I'm talking to you Florentine. Answer me. Adam: I'm not Florentine. My name is Adam Randall. Abaddon: So you are he. Your coming fulfills the Prophecy. Adam: What do you mean? Abaddon: You are known, Adam Randall, as is the woman with whom you travel. Adam: Are you... Abaddon? Abaddon: I am Abaddon. Keeper of the Key to the Abyss and Guardian Power of the Soulstone. Adam: How do you know about Rebecca and myself? Abaddon: It was said that two would come to this place in Mankind's greatest hour - that with Eternity in hand they would restore the Balance, or destroy it. Until this juncture, the woman's name was hidden to protect her, but yours... yours was known on the day that Eternity was taken from the Stone. Adam: How am I connected to this Prophecy? Who knows about me? Abaddon: All life in the Universe is connected to the Soulstone. You are connected to Prophecy by the Thread. The Thread is a Web of strands that touches each one of us. You Adam are connected in such a way that the Thread bends to you - you create rather than flow with the current. Adam: What is this place? Where am I? Abaddon: These are the Halls of Doppelgangis, demon of Insight and Personality. Adam: I've met something - he looked just like me. Abaddon: Naturally. All who come here must meet themselves. If you have any chance of success, you must destroy the Darkness all Men have in their hearts. Adam: Sounds simple enough. You have any ideas? Abaddon: The test must be passed by you, and you alone. Adam: What is this... Key to the Abyss? Abaddon: The Key is the three tests, through the arch which brought you here. Passage into Sheol is the result of the possession of the Key. Adam: The light... this red light, does it bind you here? Abaddon: I am held here by the light, yes - I do not fight against it. My only concern is Florentine's humiliation. Adam: Then you knew this would happen! Abaddon: Internment was prophesised for my soul. The light and Florentine are variables - internment was the constant. Adam: Well is there some way I can free you? Abaddon: You cannot. I must remain here if Prophecy is to be fulfilled. Adam: Why does the Soulstone need a Guardian? Abaddon: My role is that of Witness, and Vigil. I do not defend nor protect for the Stone needs not such. But my time is gone Adam, the role of Guardian will be another's after this day, as Prophecy dictates.
↑Thanksgiving Scroll, 6th Psalm: "I thank you, Lord, because you saved my life from the pit, and from the Sheol of Abaddon have lifted me up to an everlasting height, so that I can walk on a boundless plain."