After indulging in the powers of sorcery, a living thing overcome with desire will assume a perverse form. Such is the origins of monsters...
...Humans who succumb into terrible longing transform into Archfiends.
-Librom's Journal, On Archfiends, page 1
In the world of Soul Sacrifice, Archfiend is a term used to differentiate exceptionally powerful monsters that spawn from humans. These monsters are capable of greater destruction than any individual fiends and are harder to dispose, putting them at the forefront of Sorcerer's chore. Avalon regularly coordinates Archfiends extermination, usually taking pacts commissioned by the Romalus which the Sorcerers carry out; the existence of Archfiends is why Avalon is seen as dealing in paid murder, as Archfiends are basically former humans who can actually be restored into their original form, albeit at the cost of being more prone into reassuming their monstrous forms; a chance that Snctuarium is willing to take, and thus become the crux of their animosity with Avalon.
Origins[]
Archfiends certainly have humans involved in their creation and mostly were humans in origin, tough the phenomenon(s) that lead to their emergence may vary widely.
The most well-known phenomenon are humans that succumb into their heart's longing; in most backstories of Archfiends came to known by the player, the White Chalice is somewhat involved in the creation of the original Archfiends, tempting a human in peril, giving them an irresistible offer at the cost of sacrificing something or someone most precious to them. The reward is always supernaturally effective in some sense, but pushes them off humanity, body and mind. It is unknown, however if White Chalice is always involved in all cases of transformed human.
In some peculiar case, Archfiends are created out of completely different reason: the Werewolf was created out of Venatar's desire to see the supposed monster, and is created from his sacrificed eye instead of the sorcerer himself transformed. Lizardmen were created from failed attempt of executing the Elixir Black Rite, while the Bahamut is a result of symbiotic bond between a Lizardman and an Orichalcum.
Another common case of Archfiend's occurrence is trough Doppelganger effect; this happens when the corruption of an Archfiend, either through inflicted wound or through containment of its soul in the Right Arm, overwhelms a Sorcerer, transforming him/her into the very Archfiend whose desire is dominant. In some more gruesome case, a Doppelganger can have multiple Archfiend souls struggle within and end up splitting into multiple independent Archfiend, this phenomenon is known as Gemini.
Humans that were restored from being Archfiends will have the power of sorcery and become able to wield magic, regardless of Romalus origin.
Based on their supposed origins, each Archfiends are regimented based on the following category; the only gameplay implication of this categorization is the type of lure that would be effective on the Archfiend.
| The Proud
The Envious The Lustful |
The Angry The Greedy |
The Slothful The Gluttonous The Desperate |
Other
Gameplay
Archfiends are intuitively treated as bosses in the game and thus adopts the common tropes of video game bosses: larger health pool, more varied attacks and tricks, and often demand more elaborate strategy and preparation to beat. Like common fiends, they have elemental preference that decides the element they're also weak against.
Archfiends have destructible body parts called Cursed Parts, which is vaguely divided between regular Cursed Parts (denoted by red dot with Mind's Eyes) and Ill-Cursed Parts (denoted by purple). Destroying these cursed parts often becomes the reason of selective offering preparation as some offerings can take out some cursed parts better. Destroying these cursed parts might change the habit of the Archfiend in battle: some loses a certain ability related to the cursed parts, some adopts new strategy, some might even go berserk.
Destroying Archfiend's Cursed Parts will yield the player Offerings unique to that Archfiend; each Archfiend has 2 kinds of Offering (Avaricious and Gluttonous Slime share one Offering), one rewarded with any destruction by 2 units maximum, and another exclusively from complete Cursed Parts destruction rewarded maximum of 1 unit per-Archfiend. Collecting Archfiend Offerings is a huge part of completing the Ars Magicka in Delta.
If Saved and restored to human form, humans that are original Archfiends can become companions that uniquely wield both of their Archfiend-specific Offerings.