Unlock the full potential of your new Lich powers from Classical Lichdom with
Prelude to Purgatory 

Prelude to Purgatory is an addon for Undeath - Classical Lichdom that provides the player with a brand new custom skill tree. This skill tree comes with 15 individual perks, each of which falls into 5 distinct categories.

How does leveling work, and how do I access the Perk Tree?

The answer is, as intuitively as possible. Feeding your phylactery souls increases your Lichdom level, and every time you'd gain a Lichdom "perk", you gain 1 perk point (except at 35 and 45 souls). Pressing "Tab" in your lich form now brings up the perk tree.

What perks does this add exactly?

Intro & Quality of Life

Prelude to Purgatory - Your spells cost 10% less, increased to 20% in Lich form.
The Living Dead - You can be affected by food and potions, and restoration spells are fully effective.
Cardinal Sin - You can make a body that is vampiric or lycanthropic.

Mannimarco's Disciple

Appeal to Mannimarco - At the witching hour (3am to 4am) you may perform a ritual to appease Mannimarco, the King of Worms.
    Mannimarco's Favor - You have a 5% chance to find black soul gems in humanoids you kill.
Sinful Sacrament - During the ritual, you may sacrifice a human heart to double the chances of finding black soul gems.
Black Mass Hysteria - If you sacrificed a heart, you gain the Black Mass Hysteria spell for a single cast.
    Black Mass Hysteria - Master Conjuration Ritual Spell, 1063 cost - All summoned and reanimated undead gain a shadowflame cloak.

Lich's Frozen Wrath

Icy Step - While in your Lich form and in combat, you leave behind you a trail of icy spikes.
Freezing Ire - While in your Lich form and in combat, you have a cloak of frost.
Black Winter - While in Lich form, your frost spells have a chance to briefly paralyze your enemies.

Lich's Corpus

Necrotic Durability - Entering combat increases your armor by 100 points.
Necrotic Adaptability - Entering combat increases your magic resistance by 25%.
Necrotic Stride - Your lich form is 20% faster.

Staff Wielder (wow really creative naming there)

Spirit of Midnight - When entering combat with a staff equipped, you summon a midnight madonna under your control.
Conduit of Souls - While you have a staff equipped, your spells that summon or reanimate undead are 100% stronger and last 100% longer.
Viper's Strike - You gain the "Viper's Strike" spell both in your mortal form and your lich form.
    Viper's Strike - Requires a staff equipped. Enemies within 20 feet are knocked backwards and are paralyzed for 5 seconds. Direct hits also poison the enemy hit, dealing 20 points of poison damage per second for 5 seconds.

The Boring Stuff

Installation

The only complicated part about installing Prelude to Purgatory is installing the custom skill framework. Because it has a lot of requirements, it can intimidate a lot of people. However, I promise you, it's easy when you look at the instructions all in one place!

1. Install SKSE (version 2.0.19 or 2.0.20)! Gamerpoets has a wonderful short video on how to do it:
2. Install Address Library for SKSE Plugins with your mod manager.
3. Install SSE Engine Fixes as this handy video from Gamerpoets explains:
4. Download and install Custom Skills Framework with your mod manager.
5. Download and install Undeath Remastered.
6. Download and install Undeath - Classical Lichdom.
6a. OPTIONAL - Download, install, and use the Undeath Cleaner Script from the previous mod page. Doing so ensures maximum compatibility.
6b. OPTIONAL - Download and install Bug Fixes SSE. Since you already installed SSE Engine Fixes earlier, this is as simple as installing with your mod manager of choice.
5. Download and install Prelude to Purgatory.
6. Download and run the Skyrim Downgrade Patcher. make sure to use the "Best of Both Worlds" option. 

Compatibility

This mod is incompatible with any mod that edits any of the following classical lichdom/undeath scripts: 

• necrolichtrackingquest
• necrolichtransformscript
• necroreverteffectscript
• necrouclphylacterysoulscript
  

This includes my own mod, Classical Lichdom - Vampiric Lich. No need to worry though, my werepyre lich loving friend - the perk Cardinal Sin basically does what that mod does. You just need to work for it (or cheat in a few black soul gems).

This mod will have a soft incompatibility with mods that add new hearts, like in the case of Forgotten Artifacts Empowered or Heartbreaker - A Custom Killmove Mod SE. The new hearts added will NOT be useable for the "empowered" ritual. Patching is also not as simple as opening the mods in xEdit - you will need to edit the PTP_AppealToMannimarco.pex script (source files included in the main mod) and then fill in the appropriate properties in PTP_MGF_AppealToMannimarco magic effect. This also means that patches will be incompatible with each other. Why am I not supporting this? Because I don't know if I can use the script that I used in the Wintersun patch. When I learn, I might make three patches I have in mind.

Load Order

Anywhere after Classical Lichdom. In order for some perks and for leveling to work, I had to edit a few of Classical Lichdom's records. Currently, I do not know of any patches that affect these records, but you can check for conflicts in xEdit if you want to be 100% sure.

The Fun Stuff

Credits:
A MAJOR thank you to the xEdit team, without whom this mod would have been impossible.
A MAJOR thank you to meh321, DOUBLY so for his custom skill framework on which this mod is based.
A MAJOR thank you to Sorceree, for helping me test the Wintersun patch
A thank you to the Simonrim Discord Server, for feedback on early version of my mod.
A thank you to Tate's Teatime Terminus Discord Server (Keizaal Wabbajack List Discord) for feedback on early versions of my mod.