For anyone still looking for a good healer build for this, check out Dawnforgedcast ultimate healer build here:
The lvl by lvl guide here:
It's overall a Life Cleric 6 / Celestial Warlock 14 that has tons of heals, blasts out sacred flame and eldritch blast for major damage, plus allows several invocations.
I'm currently running this build at Cleric 4 so I'll see how it actually plays once I get my first warlock lvl soon! I've copied the full breakdown below in case the links ever expire for these.
***Disclaimer: The details below are not of my creation, I have not leveled past Cleric 4 in my own campaign! I also prefer point buy to standard array but it's viable regardless.
Standard Array gives you:
STR 8 DEX 12 CON 13 INT 10 WIS 15 CHA 14
Choose the Half-Elf race to gain:
• +2 CHA, +1 WIS, +1 CON.
• Darkvision 60ft.
• Immune to magical sleep effects.
• Advantage on saves vs charmed.
• Proficiency with Perception and Stealth.***
Choose the Acolyte background to gain:
• Receive aid from those who share your faith.
• Proficiency in Insight and Religion.
Start at level one as a Cleric to gain:
• Proficiency with simple weapons, light armor, medium armor, and shields.
• Proficient with History and Medicine.
• Cleric Archetype: Life.
• Proficiency with Heavy Armor
• Disciple of Life: Healing spells of at least 1st level heal an additional 2 + spell level.
Equipment at 1st level:
As a first level cleric you want to take:
• Mace ***
• Scale Mail Armor
• Light Crossbow and Bolts
• Explorer's Pack
• Equipment given by your Acolyte background
Notes on equipment:
You will eventually replace the mace with the Rod of the Pactkeeper, which may be available as soon as Character level 5. This is to support your casting ability as a Warlock, especially since Sacred Flame (one of your two main offensive spells) becomes a Warlock spell (uses your CHA based spell DC).
You do not have the Str score for heavy Armors, despite proficiency. Upgrade to the Breastplate as soon as possible.* Use the Breastplate over the Half-Plate that Andrew uses in the video to avoid taking disadvantage to stealth checks. In both the Mundane and magical versions of this armor, you are only losing 1 point of AC to Half-Plate, I think that is a fair trade.
Sell the Crossbow and Bolts during character creation for 12g 5s, you have spells.
Use your shield as your holy symbol, PHB 151.
Take the Guidance, Spare the Dying, and Word of Radiance cantrips at first level.
A Word on Cleric spells 1st level +:
As a life cleric you have specific spells always prepared, based on the level of spells you can cast. As you level up using this guide, the cleric spells you will need to prepare yourself (# = Cleric level+Wisdom modifier, max 11 as a 6th level cleric when you include all the ASI bumps and Ioun Stone) are subject to your own fancy. But, because this is an Ultimate Healer build, I recommend focusing on preparing the following list of spells as you gain access to the appropriate spell levels.***
• First level spells: Healing Word
• Second level spells: Aid, Silence, Warding Bond
• Third level spells: Magic Circle, Mass Healing Word, Remove Curse, Spirit Guardians
Why Silence, Magic Circle, or Spirit Guardians?
Like Andrew pointed out, control effects are just as good as Healing. Enemy casters in the area of a Silence spell are useless until they move out of it, allowing melee party members the chance to close in on them.
While situational to creature type, Magic Circle is a great control effect.
Spirit Guardians is also very good in that, if you find yourself in melee, you can pop this to punish enemies that don't immediately run away from you, with Opportunity Attacks to those that do.
Anyway, time to level up. First, get to Cleric 4.
At cleric 2, you get your Channel Divinity Feature once per short or long rest. As a Healer, use Preserve Life often. Turn Undead is lackluster and far too situational.
At cleric 3, you gain access to 2nd level cleric spells.
At cleric 4, you want to take the Inspiring Leader feat. Andrew explains how, as the Ultimate Healer, this is very useful. Alternatively you could take the Healer feat to make Healer’s Kits awesome.***
A Word on Warlock Spells as you Level Up:
As a warlock, you have a set number of spells known and only from 1 to 3 spell slots with which to cast them; even when they refresh every short rest. Or do you? If you check out the multiclassing rules in the PHB on page 164, you will see that, while your warlock spell slots remain separate from your cleric ones, you can cast any spell you know with either set of slots as long as the minimum or maximum spell level of a spell is of a level you have slots for.
For example, as you will see below once you reach your 9th level in warlock, your warlock spell slots become 5th level slots. You cast any warlock spell you know as a 5th level spell, BUT you can also use these 5th level slots to cast any of your 1st, 2nd, or 3rd level cleric spells for their “at higher level” effects.
Vise versa, you can also use your 1st, 2nd, or 3rd level cleric spell slots to cast your warlock spells of those same spell levels. This means unfortunately, that your 4th and 5th level warlock spells must always use warlock spell slots. The good news is that you can cast Hex as long as you have ANY spell slots available.
Warlock Spell Selection:
Just as with the cleric spells I mention above, the warlock spell selection found below are suggestions only. Feel free to change them to suit your own play style. The spells I suggest are based mostly on the philosophy that the best kind of Healing is not taking damage in the first place. To that end I have selected spells based mostly on utility or battlefield control since warlocks do not have access to restorative magics.
With the addition of Xanathar’s Guide to Everything, our key Archetype has changed from Undying Light (UA: Light, Dark, Underdark) to The Celestial (XGE pg.54-55). The changes made from UA to Official are as follows:
1 - Changes to and expansion of the Expanded Spell List. This is a minor change since most of the Expanded Spell list is offensive in nature and our spell selection process focuses primarily on healing, mitigation, and buffing spells.
2 - Our bonus cantrips Sacred Flame and Light are no longer tied to the Radiant Soul Feature. They are now given at warlock level 1 as a separate feature.
3 - Our level 1, 6, and 14 features have been swapped around. Radiant Soul is now level 6, Searing Vengeance is now level 14, and Healing Light is now level 1.
4 - Healing light is now has a range of 60 feet (from touch), has a maximum die pool of 21 (from 15), and limits your die expenditure to CHA modifier (from choice of 1 to 5). Overall, these changes are for the better, The fact that you get this feature at warlock level 1 also make you even more of an Ultimate Healer.
5 - Searing Vengeance now deals 2d8+CHA (from a static 10+CHA) and you can now choose which creatures are hit (from “all hostile creatures”).
6 - Radiant Resilience has been renamed to Celestial Resilience, but is otherwise unchanged in both feature level and what it does.
Next, take 6 levels of Celestial Warlock.
At warlock 1, you gain the cantrips Light and Sacred Flame. Choose Eldritch Blast and Minor Illusion as your basic warlock cantrips. Choose Hex and Hellish Rebuke as your 1st level warlock spells. You now have access to the Healing Light feature.
A Note on Sacred Flame:
Because we get Sacred Flame as a warlock spell, it uses Charisma as its Spellcasting modifier. This is lucky for us because we will be focusing on boosting Charisma first. It also means that Sacred Flame will enjoy the boost to effectiveness given to us by our Rod of the Pact Keeper, which increases the Spell DC of our warlock spells. This spell is one of our two main offensive spells (the other being Eldritch Blast) because this.
At warlock 2, choose Agonizing Blast and Repelling Blast as your invocations. Add Unseen Servant to your warlock spells known.
At warlock 3, choose Pact of the Tome. Gain the Dancing Lights, Message, and Thorn Whip cantrips. Add the Hold Person spell to your warlock spells known and retrain Hellish Rebuke for the Darkness spell.
At warlock 4, increase your Charisma by 2. Add the Friends cantrip. Add the Invisibility spell to your warlock spells known.
At warlock 5, choose the Book of Ancient Secrets invocation, adding Find Familiar and Tenser's Floating Disc as rituals to your spells known. Add Dispel Magic to your warlock spells known.
At warlock 6, gain the Radiant Soul feature and add the Major Image spell to your warlock spells known.
You are now level 10. Take 2 more levels of Cleric to get to level 12. You are finished with cleric levels.
At cleric 5, you get Destroy Undead as an upgrade to your Turn Undead channel divinity. Again, situational as this will only be useful against CR ½ undead.
At cleric 6, you gain a second use of Channel Divinity, and you gain your Blessed Healer domain feature.
Lastly, you will take another 8 levels of Celestial Warlock.
At warlock 7, you gain the Beguiling Influence or Fiendish Vigor*** invocation, whichever one you think is better. Add the Banishment spell to your list of warlock spells known.
At warlock 8, increase your Charisma score by 2 (20). Add the Fly spell to your list of warlock spells known.
At warlock 9, Take the Devil’s Sight invocation (Combos well if you cast Darkness). Add the Hold Monster spell to your list of warlock spells known.
At warlock 10, gain the Celestial Resilience feature. Add the Mage Hand cantrip to your list of cantrips known.
At warlock 11, you gain the Mystic Arcanum feature (6th level spell). I suggest you choose the Conjure Fey*** spell (1 CR 6 or lower Fey [Annis Hag from Volo's for example], becomes hostile if you lose concentration). Add the Dimension Door spell to your list of warlock spells known.
At warlock 12, increase your Wisdom score by 2 (18). Take the Sculptor of Flesh invocation.
At warlock 13, you gain the Mystic Arcanum feature (7th level spell). I suggest you choose the Plane Shift*** spell. Add the Fear spell to your list of warlock spells known.
At warlock 14, you gain the Searing Vengeance feature.
You are now a level 20 character. Congratulations.
A note on high level equipment:
In the video, Andrew talks over his equipment selection briefly. This is really just a wish list, but it basically breaks down like this:
Magic Item Wishlist
+3 Rod of the Pact Keeper
Ioun Stone of Insight
Rod of Resurrection***
Tome of Leadership
Various Potions of Healing
Various Divine or Arcane Spell Scrolls
At the peak of this build’s performance you are hitting targets with Eldritch Blast 4 times per casting with a +15 to hit, dealing 1d10+6 force damage+10ft knockback. Your Sacred Flame deals 4d8+6 radiant damage and uses your CHA spell DC because it is considered a Warlock spell for you.
Your Cha Spell DC is 23, your Wis Spell DC is 19.
Your AC is 23. You have 149 HP (using Andrew’s method of max hp for first 3 levels, then take the average).
You have cantrips for days, invocations, spells, and healing abilities coming out the wazoo!