Archfiends

In opposition to the Seven Archangels are their dark counterparts, envisaged as opposites in the war over the multiverse by followers of the Light and formed from inverted ideals. Unlike the mad and chaotic demons of the Abyss, these archfiends are devils and correspond to a rough cosmic order, though it’s one in which they see themselves as supreme beings extinguishing light and hope and ruling over a violent realm of terror.
Baal, Lord of Destruction Legend states that Baal has taken his name from a benevolent fertility figure whose worshippers were wiped out by an early and misguided group following the Light. This constant reminder of the Light followers own destructive potential makes many followers uncomfortable with the idea of confronting Baal directly, though he and his forces stand ready to tear down anything beautiful or harmonious as they blaze through the multiverse. Though widely considered to be the most powerful archfiend, he is not necessarily the most dangerous.
Mephisto, Lord of Hatred Opposite Kshatra is Mephisto, a being so consumed with unrelenting hatred towards everything that he (mercifully) has difficulty commanding his legions or presenting any coherent strategy. He is, however, a popular choice for evil warlocks who seek revenge. He revels in the chaos and pain sown by these warlocks, and revels just as much in their confusion as someone invariably strikes them down, to perpetuate a cycle of revenge and hatred.
Diablo, Lord of Terror Armaiti represents devotion and harmony; Diablo represents the utter isolation of the ego closed off from any intuitive knowledge of the greater Divine, utterly alone and panicking. Terror can be raw and visceral or subtle and pervasive, and Diablo specializes in both. Being master of terror makes Diablo uniquely immune to it; this means he is willing to push boundaries that others don’t, and is easily the most dangerous of the archfiends, even if his raw power is less than that of his two older brothers. Some scholars surmise that this must mean Diablo understands his counterpart and his own connection to the Divine, and while dismissed by many others, this could point towards an acceptance of his role in creation.
Azmodan, Lord of Sin Wrong actions, impure thoughts, the primacy of the physical and material over any consideration of other life, these things and more are promoted by Azmodan, who in turn feeds off them. He is Inferno’s premier tactician, goading his armies of devils and vile mercenaries with promises of sated appetites and the fulfillment of their very worst desires. Screaming hordes of savages descending on a settlement to rape and pillage are as likely to be spurred on by this fiend as a highly disciplined legion which nevertheless sows terror in a systematic fashion.
Belial, Lord of Lies The consummate corrosive courtier, Belial is the least powerful of the lords in a direct confrontation, but has sown more chaos and evil than any two other lords combined. Scholars meticulously comb their myths and stories to locate and excise seeds of his vile influence, while kings and queens who follow the Light remain ever vigilant of those who employ honeyed words with no wish to directly confront anyone. Belial is often at the root of hatred and divisiveness, unjust laws, and the horrible conditions in which commoners too often find themselves; where he is not a direct influence, he grows more powerful from those beings who engage in his preferred acts for the same reasons.
Duriel, Lord of Pain Even his name invokes pain, as a reminder that the Fallen are considered by some to have been angels who turned away from Goodness, leaving the latter incomplete. A master of all forms of pain, Duriel can inflict even subtle forms which rot away a person’s mind or soul. He is a difficult opponent to face directly, as this same expertise makes him a wicked warrior nourished by the pain of far too many.
Andariel, Lady of Anguish Despite refusing the traditional feminine suffix, Andariel is the sole feminine figure among the Lords of Evil, and represents a more subtle and existential threat than her twin Duriel; anguish is longing, and loss, and separation of the self from the Divine. It is the belief that death is something to be feared and warded against at all costs, even the deaths of others; it is doubt and fear of the unknown. Anduriel is a perverted form of Wisdom in all her glory, out of reach to those who feed her and seemingly cruel to those who feel their egos threatened.