Acolyte of the Skin enhancements

Acolyte of the Skin enhancements are available for the Acolyte of the Skin archetype (variant Warlock). Introduced in Update 58.

Overview
This tree is based on a set of passive defensive enhancements and Fire damage, as well as a brief transformation into a strong melee demonic form. NOTE ON THE BELOW: For enhancements that say "Your Fiendskin gets xxxx", a reminder that you gain Fiendskin at Warlock level 6, which you need for those to become active.

Since access to this tree explicitly blocks Enlightened Spirit enhancements, a direct side-by-side comparison between the two trees is valid.

You LOSE:
 * Access to any Pact damage that is not Fire.
 * The Aura form of the Eldritch Blast if you wish for simultaneous use of weapons alongside it
 * Free access to Medium Armor without arcane spell failure
 * Free access to Martial weapon proficiency
 * The Spiritual Retibution Light Imbue 1d6 plus up to 4 Imbue Dice, though this is potentially mitigated by the Acolyte's naturally higher possible Blast damage.
 * A spread of enhancements to Summoned creatures/hirelings/pets
 * The option of 2 Constitution stat boosts instead of Charisma boosts, and another 2 Constitution at tier 5
 * 2 fewer permanent passive max HP
 * A handful of ally boosting auras that improve ally PRR, MRR, AC, a small HP boost, a small Healing Amplification Boost, and a boost to saving throws against Fear
 * The permanent Celestial Spirit transformation giving you permanent Feather Falling and an immunity to many types of standard Knockdown and Trip effects
 * The Resist Energies spell for up to 30 resistance against Fire, Cold, Electric, Acid, Sonic damage
 * A permanent Shield spell effect for +4 AC
 * The very SP-efficient Displacement SLA, forcing you to rely on the standard spell
 * The very strong Shining Through temporary HP buffer barrier, easy to get to over 250hp, that can be frequently regenerated
 * Multiple sources of Light/Alignment Spellpower (30 total if non-pure Warlock, up to 50 as pure 20-level Warlock)
 * The Spirit Blast SLA

You GAIN:
 * Up to 18% additional Fortification
 * Up to +6 to your Fortitude save
 * Up to +30 Fire Spellpower (note this cannot affect the Core damage of your blast, only Pact)
 * Up to +34 permanent MRR and +10 MRR Cap, compared to only +16 from Enlightened Spirit in non-Aura mode (26 in Aura mode) and no cap boost
 * Up to +34 permanent PRR, compared to only +6 from Enlightened Spirit in non-Aura mode and short bursts of an additional 15 AC (16 in Aura mode)
 * Up to +10 Natural AC
 * Up to +20 permanent passive resistance to Fire, Electric, Cold and Acid
 * A permanent Nightshield effect
 * Up to an additional +18 Universal Spellpower (or only +8 on a pure level 20 warlock with Ultimate Enlightnment)
 * Up to 15% enemy Fire Resistance penetration
 * A Hellish Rebuke SLA
 * Two cone-shape Blast SLAs
 * The Beam form of Eldritch Blast
 * Multiple sources of making enemies Fear you, and double Pact damage against enemies that are in Fear status
 * A +3 boost to all Saving Throws
 * Up to +3 Necromancy DCs
 * A possible Spell Resistance boost equal to your Charisma stat
 * An additional +2 Charisma
 * The temporary transformation of Fiendish Symbiosis into a strong melee form for a brief time, for up to 1 minute with a 3 minute cooldown.

Core

 * Fiendish Form I. You gain 3% Fortification and +1 Fortitude Saves per Core ability you take in this tree. Need Warlock level 1, 1AP
 * Fiendish Form II. You gain +3HP per Core ability you take in this tree. Need Warlock level 3, 5AP spent, 1AP
 * Fiendish Form III. You gain +3 Fire Resistance per Core ability you take in this tree. Need Warlock level 6, 10AP spent, 1AP
 * Fiendish Form IV. You gain +3 Magical Resistance per Core ability you take in this tree. Need Warlock level 12, 20AP spent, 1AP
 * Fiendish Form V. You gain +3 Physical Resistance and Universal Spellpower per Core ability you take in this tree. Need Warlock level 18, 30AP spent, 1AP
 * Ultimate Fiendish Form. +4 Charisma, +20% Competence bonus to your HP. You gain Spell Resistance equal to your Charisma score. Need Warlock level 20, 40AP spent, 1AP

Tier 1

 * Resilience of Body. Get +2/+4/+6 PRR. 3 ranks, 1AP each, need Warlock level 1, Progression 1
 * Guarded Mind. You gain immunity to Fear. 2AP, need Warlock level 1, Progression 1
 * Power of Desecration: Fire. You gain 3/6/10 Fire Spellpower and 1/2/4 Universal Spellpower. 3 ranks, 1AP each, need Warlock level 1, Progression 1
 * Dark Deals. Get +1/2/3 Spellcraft, Haggle and Concentration. Rank 3, gain +1 Will saves. 3 ranks, 1AP each, need Warlock level 1, Progression 1
 * Resilience of Soul. Get +2/+4/+6 MRR. 3 ranks, 1AP each, need Warlock level 1, Progression 1

Tier 2

 * Hellish Rebuke SLA. Wreathe yourself in fiendish flame that occasionally lashes out when you are struck in melee range. For 3 minutes +1 per caster level, enemies that attack you take 1d10 Fire damage +1 per Caster level. Scales with Spellpower. SP cost 6, 3 second cooldown, 2AP, need Warlock level 2, Progression 5
 * Mindwrack. Your Eldritch Blast, Melee and Ranged attacks reduce the Will saving throw of the enemy by -1 for 6 seconds, stacks up to 4 times. 2AP, need Warlock level 1, Progression 5
 * Power of Desecration: Fire. You gain 3/6/10 Fire Spellpower and 1/2/4 Universal Spellpower. 3 ranks, 1AP each, need Warlock level 2, Progression 5, Tier 1 Power of Desecration: Fire at least 1 level
 * Nightshield. You permanently gain the effects of the Nightshield spell. 2AP, need Warlock level 2, Progression 5
 * Hellfire. Your damaging spells now bypass 5/10/15 of your target's Fire Resistance. This still does NOT pierce Fire Immunity or Healed-By effects on certain enemies. 3 ranks, 1AP each, need Warlock level 2, Progression 5

Tier 3

 * Eldritch Blast Shape: Beam. Transform your Eldritch Blast into a magical beam of Force that damages all enemies in a straight line. Scales with 125% Spellpower, while active you have -1 Pact Die. Width of AoE is rather narrow, range is very slightly less than Focused form. Does do punch-through on enemies, does NOT do punch through on destructibles. Unlike other forms, this one tends to be more effective if you disable Auto-Targeting and manually aim the shots to graze as many enemies as possible; Auto Targeting makes it aim dead-center on the torso of enemies which frequently makes it hit fewer targets. 1AP, need Warlock level 3, Progression 10
 * Devil's Bulwark I. While in any armor, your Fiendskin now gives +1 Natural AC per 2 Warlock levels. 1AP, need Warlock level 3, Progression 10
 * Power of Desecration: Fire. You gain 3/6/10 Fire Spellpower and 1/2/4 Universal Spellpower. 3 ranks, 1AP each, need Warlock level 3, Progression 10, Tier 2 Power of Desecration: Fire at least 1 level
 * Fiendish Glare SLA. Unleash your Fiendish power as you fire your Eldritch Blast in a cone in front of your eyes. All enemies (not destructibles) caught in the burst take 1d6 Evil damage plus all of the effects and damage your Eldritch Blast produces, and may become Feared just at the glimpse of your true form. Area of effect is slightly shorter and wider than the Cone stance form of the Eldritch Blast. Shares a cooldown with Cleave, and the damage scales with Spell Power. 8/6/5 second cooldown. 3 ranks, 1AP per rank, needs Warlock level 3, Progression 10. Available Metas Empower, Maximize, Intensify
 * Charisma stat boost. +1 CHA, 2AP, need Warlock level 3, Progression 10

Tier 4

 * Drink Their Fear. You deal double Pact damage to enemies that are afraid of you. 1AP, need Warlock level 4, Progression 20
 * Devil's Bulwark II. While in any armor, your Fiendskin now gives +1 PRR per 2 Warlock levels. 1AP, need Warlock level 4, Progression 20, Devil's Bulwark I at least 1 level
 * Skin Adaptation. Your Fiendskin now gives an equivalent amount of Cold, Acid and Lightning Resistance. 1AP, need Warlock level 4, Progression 20 (TESTING NOTE, check actual quantities, suspect 20 each max total, re-verify it does not give Sonic resistance)
 * Luck of the Gambler. You gain +1/2/3 to all Saving throws. 3 ranks, 1AP each, need Warlock level 4, Progression 20
 * Charisma stat boost. +1 CHA, 2AP, need Warlock level 4, Progression 20, Charisma stat boost from Tier 3

Tier 5

 * Glare of the Pit SLA. Unleash your Fiendish power as you fire your Eldritch Blast in a cone in front of your eyes. All enemies caught in the burst take 4d6 Evil damage plus all of the effects and damage your Eldritch Blast produces, and may become Feared just at the glimpse of your true form. Shares a cooldown with Cleave, and the damage scales with Spell Power. 8/6/5 second cooldown. 3 ranks, 1AP per rank, needs Level 12, Warlock level 5, Progression 30. Available Metas Empower, Maximize, Intensify
 * Devil's Bulwark III. While in any armor, your Fiendskin now gives +1 MRR and MRR Cap per 2 Warlock levels, 1AP, needs Level 12, Warlock level 5, Progression 30, Devil's Bulwark II
 * Fiendish Symbiosis. Transformation, cooldown 3 minutes. You call upon your fiendish patron, transforming into a demon for a short time. You gain 100% Fortification, heal from Fire damage and gain Natural Armor equal to your Pact Dice. While in this form you no longer Eldritch Blast at range, instead you lash out with demonic claws at a short range melee Eldritch Blast that scales with 200% Spell Power. Entering this form is so frightening that nearby enemies become Afraid. You may only maintain your Demonic form for 30 seconds, but this increases by 5 seconds for each Core ability you have in this tree. 2AP, needs Level 12, Warlock level 5, Progression 30
 * Dark Lore. +1/2/3 Necromancy DCs. 3 ranks, 1AP each, needs Level 12, Warlock level 5, Progression 30