Companion: Shadowheart - Respec required

Stats: 8Str 16Dex 15Con 8Int 17Wis 8Cha

1. Cleric - Light Domain, Guidance, Resistance, Sacred Flame, Light(Domain)
2. Cleric
3. Cleric
4. Cleric - +1Wis/+1Con, Blade Ward
5. Cleric
6. Cleric
7. Cleric
8. Cleric - War Caster
9. Cleric
10. Cleric - Conjure Flame
11. Cleric
12. Cleric - Medium Armor Master

Weapons: Club of Hill Giant Strength -> Handmaiden's Mace, Darkfire Shortbow

Shield: Ketheric's Shield

Chest: Luminous Armour

Head: Helmet of Arcane Acuity

Hands: Luminous Gloves

Feet: Boots of Striding

Neck: Amulet of the Devout

Rings: Coruscation Ring, Callous Glow Ring

Cloak: Cloak of the Weave

Elixir: Elixir of Battlemage's Power

I designed this as a companion builds as it's main focus is debuffing enemies and doesn't really have much in the way of skills to serve as a useful party face. Plus Shadowheart is right there begging for an MVP build. It's even lore-friendly depending on your choices.

As stated above this build is all about inflicting the maximum number of Radiating Orb debuffs as possible, and thanks to the combination of Luminous Armor, Callous Glow Ring, and Light Cleric you can apply a ton of them. With good positioning and enough enemies you can apply 10+ per round. Now what does Radiating Orb do? It applies a -1 per round remaining to the afflicted creature's attack rolls. A -10 to -20 on attack rolls effectively means that enemies can't hit your party without a Natural 20 and with Warding Flare that not really gonna happen.

A typical first round is to run into the largest clump of enemies and cast Spirit Guardians with your highest spell slot available, then run around until you have hit all of the enemies you can reach. Subsequent rounds will see you using your Channel Divinity, casting Fireball (this will proc the Luminous Armor too thanks to the Callous Glow Ring), or making melee attacks to boost your Spell Save DC; all the while running around to all the enemies you can to trigger Spirit Guardians.

The Elixir of Battlemage's Power is super useful on this build as it's a +3 to your Spell Save DC and you can boost it further the Helmet of Arcane Acuity all the while making melee attacks. But early on you will probably want to use Elixirs of Hill Giant Strength combined with the Shining Staver-of-Skulls until you get the Callous Glow Ring.

Origin: Wood Elf or Gith Tav/Dark Urge or Astarion

Stats: 8Str 17Dex 14Con 8Int 10Wis 16Cha

Background: Soldier or Haunted One (Dark Urge)

Proficiencies: Athletics(E), Sleight of Hand(E), Intimidation(E), Persuasion(E), Stealth, Insight, Perception, Survival, Performance?, Deception?

1. Rogue - Athletics(E), Sleight of Hand(E)
2. Bard - Mage Hand, Minor Illusion, Longstrider, Speak with Animals, Healing Word, Tasha's Hideous Laughter
3. Bard - Disguise Self
4. Bard - Swords, Dueling, Intimidation(E), Persuasion(E), Enhance Ability, Silence(Tasha's)
5. Bard - Sharpshooter, Light, Cloud of Daggers
6. Bard - Glyph of Warding
7. Bard - Plant Growth
8. Rogue
9. Rogue - Thief
10. Fighter/Wizard - Archery
11. Bard - Dimension Door, Greater Invisibility(Healing Word or Silence)
12. Bard - +1Dex/Athlete, Freedom of Movement

Weapons: Ne'er Misser, Hellfire Hand Crossbow, Phalar Aluve or Club of Hill Giant Strength

Shields: Sentinel Shield, Adamantine Shield

Chest: Yuan-Ti Scale Mail, Armour of Agility

Head: Diadem of Arcane Synergy, Helmet of Grit, Helmet of Autonomy

Hands: Wondrous Gloves, Gloves of Thievery

Feet: Disintegrating Night Walkers

Neck: Surgeon's Subjugation Amulet

Rings: Risky Ring, Eversight Ring or Ring of Free Movement

Cloak: Shade-Slayer Cloak, Cloak of Cunning Brume

Elixir: Elixir of Bloodlust

Coatings: Crawler Mucus, Combustion Oil

Specialty Arrows: Arrow of Many Targets

Illithid Powers: Favourable Beginnings, Charm, Perilous Stakes, Luck of the Far Realms, Mind Sanctuary*

This build is capable of a solo run ... and it can do so quite easily.

A standard first round for the Harper is to open with a Ranged Slashing Flourish on a weaker enemy (30-40HP and lowish AC) to proc Bloodlust, then focus the rest of their Flourishes/Arrow of Many Targets on primary high value targets like mages and primary bosses. Pop a Potion of Speed or Dash as needed to one-round high value targets.

The Soldier or Haunted One Background is key due to the Pentakill Inspiration. This gives an inspiration point any time your character kills 5 enemies in one turn. This is increadibly easy to do with this build, so you should basically always have an inspiration point on hand if you need it. Most of the time this is spent on dialog Wis saves since that is the build's one weak point.

Wood Elf and Gith are probably the strongest racial choices due to proficiencies. Astral Knowlege is ridiculously OP and Stealth/Perception are super good proficiencies to gain via race.

Start Rogue to maximize Proficiencies. Athletics Expertise is really strong early on as Shove is key for clearing threatening enemies. Sleight of Hand Expertise is extremely useful early on until you have built up a supply of Inspiration and Thieves/Trap Toolkits. The build takes Persuasion and Intimidation Expertise later as you won't really see any high DCs for these checks until late Act 1. Starting Rogue is also fairly important for Saving Throws: Bards get Dex and Cha while Rogues get Dex and Int. This is a campaign against Illithids so you want Int save proficiency, especially since that is your dump stat.

Swords Bard is key for Ranged Slashing Flourish which will pretty much double your damage output. You need a minimum of 6 Bard lvls to regain you Bardic Inspiration on a Short Rest and to get Extra Attack. This also nets Song of Rest (+1 Short Rest) so you can spend your Flourishes in every encounter to a total 24x per Long Rest. The Bard Fighting style doesn't matter much since you can't take Archery FS, I tend to prefer Dueling since I like to use a shield for passive abilities. Generally speaking though, I like to go 7-8 lvls of Bard since the 4th lvl spells are super powerful in both combat and exploration.

Fighter 1 grants Shield Proficiency and the Archery Fighting Style. Fighter 2 for Action Surge is nice but if you want 4th lvl spells you need the spoiler item below. Wizard 1 is another option to take here as it grants up to 5th lvl Wizard spells due to the spellbook mechanics though this choice might want to respec for some different Bard spells.

Spoiler required for Min/Max Fighter 2

Strait up if you are skipping the second ASI you need the Hag's Hair this +1 Stat increase lets you skip Bard 8 in favor of Action Surge.

This build will also want to take the +2 from the Mirror of Loss to reach 20 Dex.

This build doesn't take any attack spells as attacking with your dual hand crossbows is going to be a better use of your action 99% of the time. That said there are some key spell picks that really amplify the Harper's utility. Glyph of Warding, Dimension Door, and Greater Invisibility are all incredibly effective spells both in and out of combat. Enhance Ability basically means you will be rolling every skill check at advantage. You could take Hold Person instead of Silence, but Silence is super handy and I found items/coatings to be a more reliable means of paralyzing targets.

For Items: The Ne'er Misser is probably the best as Force Damage is way better than Piercing, but the Hellfire Hand Crossbow is really nice for making your off hand attacks more accurate for moping up enemies at the end of the round. You melee choice mostly matters for passives as you won't really ever be attacking with them. Phalar Aluve is the best for combat due to it's songs, but Club of Hill Giant Strength is great for Jumping and Carry Capacity. Diadem of Arcane Synergy is +3 to attack and damage rolls, but gets edged out in Act 3 by the Helmet of Grit for a 3rd Bonus Action. The Helmet of Autonomy is to swap in during dialog when you know you will be making Wis saving throws. Wonderous Gloves give and additional Bard Inspiration so effectively +4 uses per Long Rest. Risky Ring is permanent Advantage on Attack Rolls. The other ring is kinda tricky though as both Darkness and Hold Person are popular in Act 3 and weather you find Paralyzed or Blinded to be a bigger issue will probably depend on your party and playthrough. Surgeon's Subjugation Amulet is key as combined with Luck of the Far Realms this is a once per day At Will, Unsavable Paralyze on a target combine with Perilous Stakes for single rounding just about any enemy in the game.

I was just curious because I don’t usually interact with this type of system. Most of the time they just provide +2% lockpicking speed or something niche like that. You know stuff that only really matters on some builds for the highest difficulties.

But Potions of Speed, Elixir of the Colossus, and Elixir of Bloodlust are so damn good I started brewing them up anytime I got enough ingredients. It’s become almost as habitual as checking every barrel and box.