Acolyte of the Skin

I think AS could be more interesting with selectable patrons (and different play styles depending on the patron). 

It would better express the difference between warlock and acolytes, if the acolytes are connected for a specific patron, which causes acolyte to become more and more similar to her patron.

I choose Fiend, Abyss and Carceri Storm to the acolyte and I use the names of the Patron for the sake of the mood.

A theory about the origin of pacts from Candlekeep

There are beings with almost divine power who are not satisfied with their power and want to increase it further so that they can become gods. There are several legends about becoming a god:

• • • • They steal the power of a god, like Mask and Cyric. 

      • Embrace the power of a fading god, like Mystra and Mystril. 

      • He gains believers and becomes a god through their faith. 

Needless to say, the first two are quite rare. 

The powerful beings who want more (demon lords, princes of hell, demigods, greatest undead/ancient beings...) try the third for lack of a better option. They begin to share their power with mortals, who proclaim their name and power in the world. The more successful the endowed, the more people want to follow them. The more followers there are, the more the contract starts to become a belief, so they get closer and closer to godhood. 

At the same time, these contracts are not without risk for them either.

• They are not gods, their power is much more limited.

• It is not a heavenly relationship, one of the patrons can be reached through the contract holders. Thus, they have to devote energy and time to their own defense. 

Chooseable True Patron: Asmodeus or Velsharoon or Dagon

To all Patron:

• • • No autogranted spells.

    • Asmodeus (Diabolical), Velsharoon (Unhallowed) or Dagon (Demonic) variant is non chooseable, based on the choosed patron!

True Patron Asmodeus

(instead Fiend - Diabolical - Baatezu LE)

True Patron Velsharoon

(instead Abyss - Unhallowed -Undead NE)

True Patron Dagon

(instead Canceri Storm - Demonic - Tanar'ri CE)

Core

Patron's Form I

You gain 3% Fortification and +1 Pact Saves per Core ability you take in this tree.

Patron's Form II

You gain +3 HP per Core ability you take in this tree.

Patron's Form III

• • • • • Asmodeus: You gain +3 Fire Resistance per Core ability you take in this tree.

        • Velsharoon: You gain +3 Negative amp per Core ability you take in this tree.

        • Dagon: You gain +3 Cold Resistance per Core ability you take in this tree.

Patron's Form IV

You gain +3 Magical Resistance per Core ability you take in this tree.

Passive to all patron: Pact damage change to Evil for transformation duration.

Patron's Form V

You gain +3 Physical Resistance and Universal Spellpower per Core ability you take in this tree.

The transformation activation grant second wind effect, as equal level fighter.

Ultimate Patron's Form

+4 Charisma, +20% Competence bonus to your HP.

For transformation duration grant:

• • • • • Asmodeus - Fiedskin's Natural Armor, PRR/MRR bonuses increases with Pack Dice number (half warlock level + Pact Dice number). 

        • Velsharoon - Additional +1 Necromancy caster level and maximum caster level. 

        • Dagon - Your Chill/Freeze decrease enemies saves with Pact Dice number for 3 second per warlock level. 

You gain Spell Resistance equal to your Charisma score and your Align spells will use Fire/Negative/Cold Spell Power if it is higher.

Tier 1

Resilience of Body

You gain +[2/4/6] Physical Resistance Rating.

Mindwrack

Your Eldritch Blast, Melee and Ranged attacks reduce the Will saving throw of the target by -1 for 6 seconds. The effect stacks up to 4 times.

Power of Desecration - <type>

• • • Asmodeus - Fire: You gain +[3/6/10] Fire Spellpower and +[1/2/4] Universal Spellpower.

    • Velsharoon - Negative: You gain +[3/6/10] Negative Spellpower and +[1/2/4] Universal Spellpower.

    • Dagon - Cold: You gain +[3/6/10] Cold Spellpower and +[1/2/4] Universal Spellpower.

Dark Deals

+[1/2/3] Spellcraft, Haggle and Concentration. Rank 3: +1 Will saves.

Resilience of Soul

You gain +[2/4/6] Magical Resistance Rating.

Tier 2

Projection of Realm - SLA Cost 6 SP, Cooldown 3 second.

• • • Asmodeus - Hellish Rebuke: Wreathe yourself in fiendish flame that occasionally lashes out when you are struck in melee range. For 3 minutes plus one minute per caster level, enemies that attack you have a chance to take 1d10 Fire damage plus 1 per caster level. This damage scales with Fire Spell Power.

    • Velsharoon - Cloak of Darkness: Wreathe yourself in dark aura. For 10 second plus 6 second per caster level, you gain Concealment and Incorporeality equal with your caster level.

    • Dagon - Chilling Aura: Wreathe yourself in cold of depths. For 30 second plus 10 second per caster level, enemies that attack - with any type attack - you have a chance to Chilling. 

Patron's Will: SLA Cost: 5 SP, Cooldown 10 sec.

• • • • Asmodeus - Scare

      • Velsharoon - Command Undead

      • Dagon - Tentacle of Depths (2. level Conjuration spell, range double, target single):  Affected enemy must make a Fortitude save or become frozen solid for number of seconds equal to your Warlock levels, a successful save reduces to Chilling.  

Power of Desecration II - <type>

• • • • Asmodeus - Fire: You gain +[3/6/10] Fire Spellpower and +[1/2/4] Universal Spellpower.

      • Velsharoon - Negative: You gain +[3/6/10] Negative Spellpower and +[1/2/4] Universal Spellpower.

      • Dagon - Cold: You gain +[3/6/10] Cold Spellpower and +[1/2/4] Universal Spellpower.

Nightshield

You permanently gain the effects of the Nightshield spell.

External Energy <type>

• • • • Asmodeus - Hellfire:  Your damaging spells now bypass [5/10/15] points of your target's Fire Resistance.

      • Velsharoon - Deeper Darkness: Your damaging spells now bypass [5/10/15] points of your target's Negative Resistance. 

      • Dagon - Cold of the Depths:  Your damaging spells now bypass [5/10/15] points of your target's Cold Resistance.

Tier 3

Eldritch Blast Shape: Beam

Transform your Eldritch Blast into a magical beam of Force dealing damage to all enemies in a straight line. This scales with 125% Spell Power. While active you have -1 Pact damage die.

Assimilation I 

• Asmodeus - Devil's Skin I: While in any armor, your Fiendskin now grants +1 Natural Armor per 2 Warlock levels.

• Velsharoon - Life Steal I: Your Eldrict Blast (include all Eldrict base attacks) have 5% chance to steal life (restore 1 HP per 2 warlock level, scales with your negative amp). 

• Dagon - Deep Freeze I: Your Eldrict Blast (include all Eldrict base attacks) have 5% chance to Chilling enemies (no save).

Power of Desecration III - <type>

• Asmodeus - Fire: You gain +[3/6/10] Fire Spellpower and +[1/2/4] Universal Spellpower.

• Velsharoon - Negative: You gain +[3/6/10] Negative Spellpower and +[1/2/4] Universal Spellpower.

• Dagon - Cold: You gain +[3/6/10] Cold Spellpower and +[1/2/4] Universal Spellpower.

Fiendish Strike SLA [8/6/5] second cooldown. Damage scales with Spell Power. Available Metamagics: Empower, Maximize, Intensify

• Asmodeus - Fiendish Glare: Unleash your Fiendish power as you fire your Eldritch Blast in a cone from your eyes. All enemies caught in the burst take 1d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to Feared (Will vs 13 + CHA + Necromancy bonus) enemies.

• Velsharoon - Horror's Scream: Unleash your unhallowed power as you fire your Eldritch Blast as scream in a cone from. All enemies caught in the burst take 1d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to inflict 1 negative level (Fortitude vs 13 + CHA + Necromancy bonus) to enemies.

• Dagon - Wastrilith's Breathe: Unleash your unhallowed power as you fire your Eldritch Blast as breathe in a cone from. All enemies caught in the burst take 1d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to Freeze (Fortitude vs 13 + CHA + Conjuration bonus) enemies. 

Charisma

+1 Charisma

Tier 4

Dark Blessing

• • • • Asmodeus - Drink Their Fear: You deal double your Pact damage to enemies that are afraid of you.

      • Velsharoon - Consuming Curses: Your cursed enemies lose negative immunity for 3 sec per Pact Dice number if you hit them with Eldritch critical attack.

• • • • Dagon - Fragility: Your frozen enemies die instantly if you hit them with Eldritch critical attack (Bosses immune).

Assimilation II

• • • • Asmodeus - Devil's Skin II: While in any armor, your Fiendskin now grants +1 Physical Resistance Rating per 2 Warlock levels.

      • Velsharoon - Life Steal II: Improve your Life Steal (restore 1 HP and 1 SP per 2 warlock level).

      • Dagon - Deep Freeze II: Eldritch hit on Chilled/Frozen enemies inflict 1 stack vulnerability.

Essence from Patron

• • • • Asmodeus - Elemental Skin: Your Fiendskin now grants an equivalent amount of Cold, Acid and Lightning Resistance (Maximum of 20).

      • Velsharoon - Damning Shadow: Your critical damage from Eldritch attacks inflict Cursespewing.

      • Dagon - Fata Morgana: You have caster level % chance to fully absrop any attack once per 20 second. 

Luck of the Gambler

+[1/2/3] to all Saving Throws.

Charisma

+1 Charisma

Tier 5

External Disaster SLA [8/6/5] second cooldown. Damage scales with spell power. Available Metamagics: Empower, Maximize, Intensify

• • • • Asmodeus - Glare of the Pit: Unleash your Fiendish power as you fire your Eldritch Blast in a cone from your eyes. All enemies caught in the burst take 4d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to Feared (Will vs 16 + CHA + Necromancy bonus) enemies.

      • Velsharoon - Bodak's Death Gaze: Unleash your Unhallowed power as you fire your Eldritch Blast in a cone from your eyes. All enemies caught in the burst take 4d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to inflict 1 negative level (Fortitude vs 16 + CHA + Necromancy bonus) to enemies.

      • Dagon -  Obyrith's Breath: Unleash your demonic power as you fire your Eldritch Blast as breath in a cone from. All enemies caught in the burst take 4d6 Evil Damage, plus any other effects and damage your Eldritch Blasts produce. Damage have chance to Freeze (Fortitude vs 16 + CHA + Conjuration bonus) enemies. 

Assimilation III

• • • • Asmodeus - Devil's Skin III: While in any armor, your Fiendskin now grants +1 Magical Resistance Rating and Magical Resistance Rating Cap per 2 Warlock levels.

      • Velsharoon - Life Steal III: Life Steal duobled vs cursed enemies (restore 1 HP and SP per warlock level). 

      • Dagon - Deep Freeze III: Your critical Eldritch hits automatically freeze chilled opponents, without save chance. (Bosses immune.)

Dark Lore

Choose: +[1/2/3] Necromancy or Conjuration DCs

<type> Symbiosis

Transformation, cooldown 3 minutes, you may only maintain your form for 30 seconds, but its duration increases by 5 seconds for each Core ability you have in this tree. 

While in this form, you no longer Eldritch Blast at range. You can use your Eldritch Blast as typed short range melee attack (scales with 200% Spell Power).