Some edits I don't remember making. Just uploading it to not invalidate my saves. Below is the original description by rottensunlight@gmail.com.

 This addon is supposed to alter the cursed/Darkness tree

to make it useful, while changing as little as possible. I have long
since gone past "as little as possible". I also added the Inner Darkness
tree, an advanced tree meant to supplement Darkness the way that Advanced
Shadowmancy supports the Shadows tree.

-- Creeping Darkness: I lowered the cooldown, I set the number of seeds

            of darkness to increase appropriately with talent
            level. The darkness now inherits a weaker version
            of the debuffs of other debuffing abilities you
            learn once those talents reach level 4. In
            particular, Dark Torrent, and Dark Tendrils. The
            strength of the debuffs are determined by the
            talent level of the talents from which the
            debuffs are stolen, and your mindpower. The
            density of the darkness is based on mindpower and
            talent level, filling up to 75% of the given aoe 
            at 100 mind power and talent level 5.

-- Dark Vision: I increased the max range of the vision to 7

            squares, to enable one to target Agony and
            Hateful Whisper correctly. I also boosted the
            movement speed buff slightly.

-- Dark Torrent: I set the ability to always leave creep behind

            instead of randomizing a core part of the ability.
            I also increased the damage very slightly.

-- Dark Tendrils: I made it faster, with scaling based on talent

            level, and the damage of the darkness it leaves
            behind is improved. I also added an extra
            tendril at talent level 6.

-- Grudge: This gives you a hate/life heal, while

            inflicting the Grudge debuff, which will take
            back the life it healed, plus a little more, 
            making you bleed creeping darkness all the while.

-- Veil Walk: This is just a short range teleport, with the

            ability to switch your place with opponents. It
            gains range with talent level. It is instant if
            you are stepping into your creeping dark. It
            also cuts fear immunity, dark resist and mind
            save when you switch with an enemy.

-- Heartless: This sustained ability burns hate to deal a

            small amount of dark damage on top of every
            blow you deal, and also makes enemies leave
            behind pools of darkness when you kill them.

-- Dark Blood: This ability is pure damage smearing. It collects

            all the damage you take in a single pool and
            portions it out to you over the following turns
            at a set rate.

I have also unlocked the Fears tree, and changed it to be like the version
of Fears in HousePet's afflicted rework. However, the fear effects
themselves have been altered. In particular, the fears that inflict
damage are now allowed to crit, and some of the fears were locked so as to
not inflict brainlock. This has been removed.

I have significantly buffed Gestures to the point of being absolutely brokt,
in the hopes that they'll make a possible alternative to psiblades. I'll
just have to keep buffing them until you don't have to take psiblades, and
then tune them until they aren't crushingly oppressive.

Forgo arms to ravage your foes with fist and claw.
While unarmed, you gain all the weapon/shield bonuses of Surge, Cleave, and Repel.
Surge, Cleave, and Repel are no longer mutually exclusive while you are unarmed and will not put the other talents on cooldown when activated. If you equip a weapon while any of these are active, they will deactivate.
Attacks which would strike with a mainhand weapon or shield will use your unarmed stats for the weapon and/or shield attack.
Weapons Mastery will apply to unarmed combat and Willpower will be used in place of Dexterity as a damage modifier for gloves and gauntlets.
You learn the Grappling talent tree, unlocked at 1.3 mastery. Stamina cost for these talents is converted to Hate (at a ratio of 4:1).

Adds the Nocturne, a Darkness-based Doomed evolution.

The Nocturne gains extra proficiency in the Cursed/Darkness tree, as well as access to two new high-level trees:

Nightwalker - Use the darkness to escape, approach, hide, heal, and invisibly strike your foes.

Umbra - Your darkness takes hold inside your enemies, giving you unprecedented power against them.

Adds the Schizophrenic class.

Note: This is the first release and balance may be weird because I am not very good at balancing things. If you want a bit more polished class, wait a few days.
Adds a new class, the Lost, designed by Thornstromb and developed by me.
The Lost is a new Afflicted class based around a hybrid of Archery and Stealth. Skulking in the shadows, the Lost is filled with a piercing hatred for the living.
A nasty glass cannon that relies on tools and inscriptions for survival, but does atrocious amounts of damage while undetected. You have an alternate version of stealth that never breaks, and while you have no inbuilt source of stamina regen, as a Willpower-main class you'll have plenty of stamina for most fights.

Class Details
-- Base Stats

+ 4 Dex / +4 Will / +3 Cun

Starting Life - 110 (as Archer and Cursed)
Life Rating: +1 (Cursed is +2, Archer is +0)
Starting Gear: (Same as Archer)
Archery Prowess 1.3 (as Archer)

-- Class Skills
Archery Prowess 1.3 (As Archer)
Predator 1.3 (As Cursed) (NOTE: Outmaneuver is tweaked to affect both melee and ranged attacks via weapon damage trigger. This should have no functional effect on Cursed.)
Trapping 1.3 (As Rogue)
Fears 1.3 Locked (As Afflicted)
Sniper 1.3 Locked (As Archer)

New trees:
Hunter 1.3 -- Archery skills
-- Silent Shot
Active - 5 Hate 10 Stamina - CD 6
Deal increased weapon damage, can mark and boost stealth power.
-- Leech Shot
Active - 10 Hate 15 Stamina - CD 6
Deal increased Weapon Damage with life steal.
-- Shadow Shot
Active - 10 Hate 20 Stamina - CD 6
Deal standard weapon damage and additional Darkness Damage, potentially blind the target.
-- Erupting Shot
Active - Cost 20 Hate 30 Stamina - CD 20
Deal significant weapon damage and prevent stealth from working for several turns.

Twisted 1.3 -- Utility Skills
-- Hate’s Draw
Passive
Bow Weapon Mastery, converts Str scaling and requirements on ammo/bows to Will, gives Shoot a 10% chance to Mark.
-- Skulk
Stalk, but for ranged.
-- Eternal Harvest
Passive
Gain Unnatural Body style healing when removing marks from targets.
-- Loathing
Sustain - Reserve 20 Hate
Add Darkness Damage to ranged attacks and causes Random Gloom when you remove a Mark.

Shroud 1.3 -- Stealth Skills
-- Cloak in Shadow
Sustain - Reserve 20 Hate
Gain a modified version of the stealth talent that does not disable light radius or give infravision and does not break when actions are taken.
-- Shadow Stalker
Passive
Targets who cannot see you have a chance to receive a Random Gloom and a high chance to be Marked.
-- Deep Shroud
Sustain - Toggle
Whether sustained or not, gain bonus stealth power while standing on unlit tiles. When toggled on, gain Infravision and reduce your light radius to 0 on all tiles.
-- Path of Shadows
Active - 10 Hate - [25-12] CD - [3-7] Range
You may always move instantly through cursed miasma from Savage Hunter (in the Predator tree), and you can activate this skill to generate a cursed miasma tile and immediately teleport to it.

-- Generic Skills
Combat Training 1.3 (As Core)
Survival 1.0 (As Core)
Dark Sustenance 1.3 (As Doomed)
Cursed Form 1.0 (As Afflicted)
Cursed Aura 1.0 Special (As Afflicted)

Adds the Fallen Meditant class. The Fallen was once a monk; training in a natural combat style upon a mountain. They have been cast down.

Adds the Banished, an afflicted class that pours its hate into its arrows and shadowy powers.

Fallen has been added to the base game as an evolution for Sun Paladins

This addon contains the original version, a base class afflicted/celestial hybrid.

Fallen are unlocked alongside Sun Paladins.
If you want to skip straight to it, I recommend using: https://te4.org/games/addons/tome/ignore-raceclass-locks

Please report any bugs on the forum thread.

This class is originally inspired by the enemies John and Aluin, Afflicted Sun Paladins.

Fallen have a mix of old and new trees.
Enemies do not generate with Fallen talents.

Celestial Combat
Shadows
Gloom (locked, level 0)
Bloodstained: By making bloody attacks, increase your positive energy.
Darkside: Consume positive energy for attacks and mobility.
Shadows of Suffering (locked, level 10): Use your shadows for defense and control.
Crimson Templar (locked, level 10): Magical abilities that manipulate bleeding and the battlefield.
Black Sun (locked, level 10): Celestial attacks using gravity.

Celestial Light
Cursed Aura
Self-Hatred: Spend life for Hate and power.
Dirges: Useful songs in the style of Chants and Hymns.

Adds game options related to equipment curses and cursed auras from the Defiling Touch talent:

• "[ZOmnibus] | Show power of cursed auras", which modifies the buffs display for cursed auras to include the "curse power" based on number of worn equipment pieces with each curse type (including +2 bonus from Defiling Touch, if applicable).
• "[ZOmnibus] | Tag cursed items in equipment", which adds an extra curse-related keyword to a worn cursed item's listing in the equipment display.

Also adds a tooltip to Defiling Touch's Cursed Aura Selection dialog, showing the effect of each curse if you select it.

Also available as part of the ZOmnibus Addon Pack and ZOmnibus Lite.