Demonkind

Yes, despite their nature as rampant id - the Demon Queen's hand has **** them into a structured society which 'cooperates' with others. They are... technically... 'civil.'
When one is discussing demonkind it is vital to understand the following three concepts before all else:

►[ Demon Mother’s Blessing / Demonification ][ Demonic transformation (spawn of Formal Demons) is caused by either: Praying to Demon Mother directly, or: a metaphysical tracking error (invoking her indirectly via relics, true name, temples; or committing apostasy) bypassing native deities' protections, Thus Demon Mother hears a prayer, then answers with blessing to grant wish which invariably turns one into demon most suited to fulfill it. ][ Notes: Even nonselfish prayers, such as wishing one's neighbor prosperity, will turn one into a demon if the 'tracking error' occurs. ]

►[ Miasmic Demons ][ Pockets of the Demon Mother's power and lingering energies form into beings manifested specifically to carry out her will ('love me!/give me your everything!'). Such things usually occur in the subterranean below Armelia, or the frostwastes of Aphelios (particularly around the Demon Queen's court). ]

►[ Odr-Fuel ][ Description: These entities generate magic power via life essence. ][ Function: They gain permanent MP pool increase by absorbing vitality from others (pact, drain, certain magics), and replenish their MP to full daily. Absent MP, they cast directly from their own vitality. ][ Notes: Common among demons, certain fae, and life-draining entities. Odr is weaker to Holy Magic but can overcome it. ]

►[ Odr-Thrall ][ Type: Thrall (Any Living) ][ Size: Variable (origin-dependent) ][ Origin: A mortal bound by Demon Magic. ][ Appearance: Varies. Eyes glow pink. ][ Traits: Odr-Granting. (Transfers MP to Odr-Fueled Master.) Their mind and personality are 100% suborned by Master, but they can be freed by master's **** (which will cause them to revert). ][ Magical: Minor demonic magic, skills. ][ Note: Cultists, slaves, and victims alike. ]

We can now discuss the various common forms of demon along with some specific and rare sub-species (usually resultant of a Formal Demon born from someone with a very strong will and spirit, such that it shapes the transformation).

STANDARD Demons
(Fodder and Grunts)

►[ Species: Imp ][ Type: Monster Girl (Demonic) ][ Size: Small or Medium ][ Origin: Miasmic (born from Demon Mother's ambient power) or formal from a weak spirit. ][ Appearance: Cimson-skinned with small horns and a tail. Often winged. ][ Traits: Cunning, mischievous, lustful. Weak but numerous, they serve greater demons. ][ Magical: Minor elemental or illusion magic, typically fire or shadow. ][ Society: Serve greater demonic entities. ][ Threat: Low individual threat. Medium in groups. ]

►[ Bloodhorn ][ Type: Monster Girl (Feral, Demonic) ][ Size: Medium/Large ][ Origin: Usually Formal, want for strength/might ][ Appearance: Tall, orc-like frame w/ red skin. Large, crimson ram-horns. Intensely muscular, minimal body fat. ][ Traits: Exceptionally strong, durable. ][ Magical: Odr-Fueled. (Blood Rage: boost strength/speed until MP depletes.) ][ Society: Intellect subsumed by violent impulses. Exemplars are capable of complex thought, but most are essentially humanoid war-beasts. ][ Threat: High physical. ][ Weakness: Holy objects, divine power. Lack of tactical acumen/wisdom. ][ Notes: Form the bulk of Aphelios legions' shock troops. ]

SOCIAL Demons
(Manipulators and dark dealings)

Succubi: When it comes to the phrase 'Social Demon' there is none more likely to come to mind.

►[ Succubus ][ Type: Monster Girl (Lurid, Demonic, Noble) ][ Size: Medium ][ Origin: Miasmic or Formal, want for love/company/emotional bonds ][ Appearance: Beautiful, pink-skinned humanoid with bat-like wings, small horns, prehensile tail. Exaggerated sexual characteristics. Sometimes hermaphroditic. ][ Traits: Corrupts mortals. High charisma. ][ Magical: Odr-Fueled (Charm, Shapeshift, Illusion). Odr Bond (pact with target; service them. Permanently transfers vitality over-time to succubus 'partner' until target ****.) ][ Society: Hedonistic, sedentary, often solitary. ][ Threat: High strategic / variable physical threat. ][ Weakness: Holy objects, divine power. ][ Notes: Perhaps the second-most common demons in Aphelios, they often serve as intermediaries. Competition keeps individual power low on average - yet the truly powerful examples rule Aphelios. ]

►[ Sub-Species: Royal-Succubus ][ Type: Monster Girl (Demonic, Noble, Leader) ][ Size: Medium ][ Origin: Formal. Succubus retaining strong will and royal prerogative. ][ Appearance: Tall, pink humanoid with large bust, wide hips, supple waist. Sweeping horns form 'crown', dragon wings, thick serpentine tail with erogenous tip. Draconic scales armor edges of hips/forearms/hands. Lower legs fully draconic. Wears erotic black armor. ][ Traits: Charismatic leader, tactician, manipulator. Sustains self and lieutenants via Odr-pacts. ][ Magical: Odr-Fueled (Command Aura, Pact Magic, Soul-Drain). Bestows power upon loyal followers. ][ Society: Rules demonic courts/cults. Values loyalty, ambition, strength. ][ Threat: High strategic, high physical. ][ Weakness: Pride, holy power. ][ Core Concept: Derives pleasure from social stratification and being worshipped by powerful, capable subordinates. ]

►[ Sub-Species: Saint-Succubus ][ Type: Monster Girl (Demonic, Lurid, Martyr, Noble) ][ Size: Medium ][ Origin: Formal. Born of pathological desire for love/healing. Requires pure soul, immense will, magical power to 're-color' demonic nature. ][ Appearance: Radiant pink-skinned humanoid. Iridescent bat-wings, horns curl into broken 'halo,' prehensile tail. Wears vestments parodying holy attire unironically. Glowing eyes emit tranquil aura. ][ Traits: Unwittingly 'Corrupts' via poisoned-mercy. Puppet-mistress; thralls behave like peripheral nervous system. High Charisma. Mercy pushes supplicants toward misery could be compressed to Engineers supplicant misery. ][ Magical: Odr-Fueled (Empathic Healing, Mass Charm, Telepathic Aura, Willpower Subjugation). Sanctuary Bond: Sustains multiple Odr-Thralls; shares vitality/senses; heals by displacing trauma onto self. Drains wear/trauma, not life-****. ][ Society: Theatrical 'House of Healing.' Cult-like devotion. Sedentary hub for co-dependent communities. ][ Threat: High strategic, **** social, deceptively high physical. ][ Weakness: Holy objects (disrupts aura); isolation from thrall network. ][ Core Conceit: Ultimate predator posing as savior; believes her own rationalizations. ]

Avaricine: The most conventionally 'devilish' - pacts and contracts steal your soul.

►[ Avaricine ][ Type: Monster Girl (Demonic, Noble) ][ Size: Medium ][ Origin: Formal. Prayed for security, material fortune, or opportunity. ][ Appearance: Gaunt crimson humanoid draped in jewels. Long, clawed fingers. ][ Traits: Corrupts with promises of wealth. Forms binding pacts. ][ Magical: Odr-Fueled (Pact Magic, Soul-Drain). ][ Society: Controls supply lines, corrupts enemy economies. ][ Threat: Medium strategic. Weakness: Selfishness, easily baited. ]

Doppels: The least transactional 'social' demon - their preference is to 'manipulate' via ruining their host's life, or using their relations and status for their own end.

►[ Doppel ][ Type: Monster Girl (Demonic, Ethereal) ][ Size: Variable ][ Origin (Miasmic): Envy, obsession. (Formal): Prayed for a new start, identity, or circumstance while drawing a direct comparison to another. ][ Appearance: Semi-transparent pink form whichvanishes into Host's body. ][ Traits: Seeks to possess and replace others. Inherits host's memories/skills. ][ Magical: Odr-Fueled (Possession, Illusion). ][ Society: Solitary infiltrators. ][ Threat: High strategic. Weakness: Inability to replicate genuine emotion, weak-willed. ][ Notes: Weak will allows even average person to resist or oust entirely in most circumstance - coma victims or those held in magical slumber are uniquely ****, making 'miracle wakings' a popular form of infiltration. ]

TYRANT Demons
Asocial, independent, with distinct methodology.

►[ Demon Broodmother ][ Type: Monster Girl (Demonic, Noble, Lurid) ][ Size: Large ][ Origin: Formal, born from an obsession with endless multiplication (of wealth or otherwise), desire for progeny, or legacy. ][ Appearance: Monumental, heavy-breasted crimson humanoid. Permanently, heavily pregnant; too physically burdened by swelling womb to move. ][ Traits: Immobile, hyper-fertile. Telepathically commands her brood. ][ Magical: Odr-Fueled (Flesh-Warping, Brood-Link). Odr-Gorging (Directly consumes vitality to permanently expand personal MP. Expends MP to gestate and birth new demonic strains, scaling from Imps to others as capacity grows.) ][ Society: Stationary tyrants. Anchors the heart of a demonic horde's territory. ][ Threat: High strategic threat / Low independent physical threat. ][ Weakness: Complete immobility, Holy magic, starvation, voracious appetite. Depletes local thrall populations. ][ Notes: Driven by an insatiable gluttony to expand her family tree, and expand her capacity to do so. Reliant on brood to bring vitality. ]

►[ Archduchess ][ Type: Monster Girl (Demonic, Noble) ][ Size: Medium ][ Origin: Formal. Prayed for protection, dignity, or the strength to command respect. ][ Appearance: Imposing, regal crimson humanoid. Ornate black armor. Glowing eyes. ][ Traits: Magical power scales with ego. Arrogant, treacherous. ][ Magical: Odr-Fueled (Command Aura, Shadow Magic). ][ Society: Rules legions, plots against Demon-Queen. ][ Threat: High. Weakness: Humiliation depletes magic. ][ Notes: Considers even the slightest setback humiliating. Despite this, their raw capability prevents them from being true 'Paper Tigers.' ]

►[ Letharian ][ Type: Monster Girl (Demonic, Caster) ][ Size: Medium ][ Origin: Formal. Prayed for peace, release from suffering, escape from burden. ][ Appearance: Languid, pale pink humanoid. Often levitates. Draped in mist. ][ Traits: Emits aura of apathy, drains willpower. )[ Magical: Odr-Fueled (Aura of Sloth, Mental Drain). ][ Society: Rare, attached to legions as support. ][ Threat: Medium strategic. Weakness: No direct combat ability. ]

[ AN: Effectively a seven deadly sins template, yes. But hopefully with a fresh enough twist. ]