General Gameplay Goals

The overall goal with this class was to create a support class/healer that has a 'button to click' every turn.  My favorite thing to do in MMOs/DnD is heal, and unfortunately this is an option that is often lacking in games.  I like using skills and having choices, but often felt in BG3 that using a spell slot was like using potions in Skyrim or elixers in Final Fantasy -  I hoarded them even though there was no reason too!

------------------Now with controller support thanks to mrdustm4n!--------------------------------------- Gameplay

All spells the Priest learns are cantrips, and this class utilizes a new resource called Holy Power to cast more powerful spells.  Holy Power is gained by Long Resting or casting spells which generate Holy Power, and is initially capped at 5 and later increases to 10.  You keep Holy Power between fights.  Spells are learned at fixed levels and gain power by learning increased Ranks (Heal, Rank 1 -> Heal, Rank 2 -> etc.), and many scale with Wisdom.

The Priest has two subclasses selected at level 1, Holy and Shadow.   The Holy Priest is focused on supporting allies and healing, while Shadow Priest supports and deals damage.  

This is a support class!  While the Priest can deal a good amount of damage, it excels at support.  This generally means healing, shielding, fearing enemies or providing allies additional actions instead of directly dealing damage.  Pairs well with the Warrior Class.
Spells - Holy Power Generators: Each Holy Power generator generates 1 Holy Power when cast, and can only be cast while in combat.
Smite - Action - Deals radiant damage 

Power Word: Shield - Bonus Action - Gives an ally temporary HP equal to the double your wisdom modifier for 10 turns.

Lesser Heal - Bonus Action - Heals a target

Renew - Bonus Action - Heals a target for the double your wisdom modifier each turn for 3 turns

Shadow Word: Pain - Bonus Action - Deals necrotic damage to a target each turn for 3 turns

Shadow Word: Death - Action - Deals necrotic damage to the target, if the target has more than 50% HP damages you as well

Spells - Holy Power Consumers: Some spells change Holy Power costs as they gain Ranks, for example Holy Fire, Rank 1, Rank 2, and Rank 3 costs 1 Holy Power, but Holy Fire, Rank 4 costs 2 Holy Power.  Only Rank 1 costs are shown below.

Holy Fire - Action - 1 Holy Power- Deals radiant damage to a target and then fire damage each turn for 3 turns.

Heal - Action - 1 Holy Power - Heals a target for die roll + Priest Class Level.

Penance - Action - 2 Holy Power - Hurls 3 balls of light dealing radiant damage to an enemy or healing an ally.

Power Infusion - Action - 5 Holy Power - Infuse you and an ally with power, giving each of you an extra action on the next turn.

Guardian Spirit - Action - 5 Holy Power - Place a buff on an ally, when that ally reaches 0 HP they will be healed to full instead.

Mind Blast - Action - 2 Holy Power - Deals necrotic damage and may fear an enemy for 2 turns

Void Blast - Action - 3 Holy Power - Deals necrotic damage and will fear a group of enemies for 1 turn

Inner Focus - 4 Holy Power - The next spell you cast does not cost an action (but will still cost Holy Power!)

Prayer of Mending - Bonus Action - 3 Holy Power - Heals an ally for die roll plus Priest Class Level next time they take damage

Purify - Bonus Action - 2 Holy Power - Remove any diseases, charm, or fear effects from an ally

Mind Flay - Action - 4 Holy Power - Deal necrotic damage and slow an enemy, concentration spell which will allow you to recast for an action on the same enemy for 10 turns. 

Power Word: Barrier - Action - 3 Holy Power - Place a ring of light on the ground for 3 turns which gives allies +1 AC and +2 to all stats while they are within the effect

Spells - Other
Power Word: Fortitude - Action - Gain +2/4/6 constitution until next long rest.

Bonus as an Action - Toggle - This is a class action that will allow you to cast any Priest Bonus Action spell as an action.  Toggle on to make bonus action Priest spells cost an Action point, toggle off to return them to a Bonus Action cost.  

Passives Gained
All Priests
Level 3 - Inner Focus - You may cast Inner Focus

Level 4 - Feat

Level 5 -  Light, Shadow, and Balance - You may cast Renew, Power Word: Shield, and Shadow Word: Pain on two targets

Level 6 - Inspiration - Power Word: Shield now adds +1 AC as well as temporary HP - Note: This adds a new spell that is also called 'Power Word: Shield' (but has a different description), make sure you remove the old PW:S from your cast bar and use the new one!

Level 8 - Feat

Level 11 - Feat

Holy
Level 2 - Binding Heal - Whenever you heal another, heal yourself for half your level. Triggers on each Renew and Penance heal.

Level 5 - Closer to the Light - Whenever you cast a Holy Power Generator, you generate an additional Holy Power

Level 9 - Max Power - You may cast Power Infusion on two targets instead of one

Level 10 - Mindful Aid - You add your Wisdom modifier to all healing done

Level 12 - Angelic Form - You exude an aura of light, gaining 2 Holy Power and healing all allies in its effect for 10% of your maximum HP every turn, can be toggled.

Shadow
Level 2 - Life Leech - You are healed for 20% of the spell damage dealt

Level 5 - Shadow Word: Mastery - Shadow Word: Pain now lasts until the target dies, and Shadow Word: Death no longer damages you if the target has more than 50% HP.

Level 9 - Void Blast - You gain the ability to cast Void Blast

Level 10 - Mindless Destruction - You add your Wisdom modifier to all spell damage

Level 12 - Shadowform - Adds 10% damage to all spell damage dealt, and you gain an aura that damages enemies for 10% of your maximum HP each turn. Can be toggled.

Install

Install the .zip or .pak using Baldur's Gate 3 Mod Manager

Baldur's Gate 3 Mod FixerBaldur's Gate 3 Script Extender
Improved UI + Improved UI AssetsNotes
This is my first mod and I am sure the balancing is off and bugs exist.  DnD 5e wasn't really meant to have healing equal to damage, but it is something I enjoy.  You will likely not need to short/long rest to heal anymore (though I still had to a few times!).  Please let me know of any bugs you find, I don't have a ton of time but will try to fix things as they show up.  If you have balancing suggestions let me know too please. I think levels 10+ are powerful, but balancing can be difficult since a playthrough is like 40 hours.  Holy level 12 has a tremendous amount of healing, but I've played a Holy Priest since 2006 so I am biased.
This mod only has skills up through level 12, but I added a blank level 13 so you can multiclass out of Priest after level 12 if you wish.