BG3 Illithid Powers Guide: Should You Use Tadpoles? Every Power Ranked

What Are Illithid Powers?

Throughout BG3, you find Illithid Tadpole specimens (small jars containing mind flayer parasites). Consuming one unlocks the Illithid Powers skill tree, accessible via the hotbar (brain icon). Each additional tadpole unlocks or upgrades a power.

Where to Find Tadpoles

Location	Count	Notes
Nautiloid tutorial	1	On a dead thrall near the helm
Emerald Grove	1	The dead True Soul dwarf (Edowin) near the Owlbear cave
Blighted Village	1	Lump the Enlightened drops one if killed
Goblin Camp	3	Each goblin leader (Gut, Minthara, Dror Ragzlin) drops one
Creche Y’llek	2	Zaith’isk device and githyanki captain
Underdark	1	Duergar camp
Act 2 (multiple)	5+	Various Absolute cultists and Thorms
Act 3	5+	Various Mind Flayer Colony and Absolute forces

Total: ~20-25 tadpoles across the entire game.

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Power Tier List (Ranked)

S-Tier — Must Unlock

Power	Effect	Why
Favorable Beginnings	+1d4 to first attack roll or ability check against any target	Free Guidance on every new target. Costs nothing. Always active.
Luck of the Far Realms	Turn a successful attack into a Critical Hit (once per long rest)	Guaranteed crit. Combine with Paladin Divine Smite for 100+ damage.
Cull the Weak	When you reduce an enemy below its number of illithid powers, it dies instantly	Execute threshold. Kill low-HP enemies without spending actions.
Psionic Backlash	Reaction: deal 1d4 psychic per tadpole consumed when an enemy within 9m casts a spell	Free damage. Punishes enemy casters.

A-Tier — Strong

Power	Effect
Perilous Stakes	Heal a creature for 2d8 when it attacks, but it becomes Vulnerable to all damage
Ability Drain	Attack reduces target’s ability score by 1
Psionic Dominance	Reaction: counter an enemy spell of level ≤ your tadpole count
Black Hole	Pull enemies toward a point + Slow them for 2 turns
Fly	Gain fly movement speed

B-Tier — Situational

Power	Effect
Charm	Charm an enemy as a reaction
Displace	Reaction: increase enemy’s miss chance
Shield of Thralls	Grant 10 temporary HP to an ally
Concentrated Blast	Bonus Action: deal 3d6 psychic, must be concentrating

D-Tier — Skip

Power	Why Skip
Transfuse Health	Costs your HP to heal an ally. Your HP is more valuable. Use a potion instead.
Stage Fright	Disadvantage on attacks but ends when target hits anything. Too conditional.

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Astral-Touched Tadpole (Act 3)

At the start of Act 3, the Emperor offers you the Astral-Touched Tadpole. This is a major choice:

Benefits

• Unlocks the outer ring of Illithid Powers (Fly, Black Hole, Mind Blast)
• Your character’s eyes turn black with glowing irises (cosmetic change)

Consequences

• Permanent visual change: Black veins across your face
• Companion reactions: Most are uncomfortable. Some have strong opinions.
• Story: Makes certain endgame choices harder to resist

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Best Powers for Specific Builds

Build	Priority Powers
Melee Fighter/Barbarian	Luck of the Far Realms, Favorable Beginnings, Psionic Backlash, Ability Drain
Rogue/Stealth	Luck of the Far Realms, Favorable Beginnings, Charm, Fly
Cleric/Support	Perilous Stakes, Shield of Thralls, Psionic Backlash
Wizard/Sorcerer	Psionic Dominance, Favorable Beginnings, Black Hole, Cull the Weak

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Story Consequences: The Full Truth

Minor spoilers ahead — skip if you want a completely blind playthrough.

Consuming regular tadpoles has minimal story consequences:

• Your guardian/Emperor approves
• Your companions have dialogue reactions but nothing permanent
• A late-Act-3 Wisdom saving throw (DC 21) to resist becoming a mind flayer, but this is influenced by many other factors, not just tadpole consumption
• No ending is locked out by consuming tadpoles

The Astral-Touched Tadpole has more weight:

• Permanent visual transformation
• Harder to resist certain Act 3 choices
• But still reversible through specific story paths