Using Illithid powers in Baldur’s Gate 3 makes you stronger in combat and dialogue, but it also pushes your character down a more “Mind Flayer–aligned” path with story and relationship consequences.

Quick Scoop: What Happens If You Use Illithid Powers (BG3)?

In BG3, Illithid powers come from the tadpole in your head, and you unlock more of them by consuming additional tadpoles you find. These powers are extremely strong and can change how you play both in fights and in roleplay scenes.

Here’s the core of it:

  • You gain a special Illithid skill tree with powerful psionic abilities.
  • The more you use and evolve these powers, the more your character embraces the Mind Flayer influence, which is reflected in cutscenes, NPC reactions, and possible endings.
  • You are not instantly “locked into” a bad ending just for using a few powers, but full commitment to them heavily shapes the late‑game outcome.

Gameplay Effects: What You Actually Get

Illithid powers are basically a bonus mini-class tree layered on top of your normal build.

Some examples from the tree:

  • Favorable Beginnings – Your first attack roll or ability check against a target gets a bonus equal to your proficiency bonus, making early actions more reliable.
  • Force Tunnel / Repulsor – Charge forward or blast enemies away without provoking opportunity attacks, letting you rearrange the battlefield in your favor.
  • Concentrated Blast – Deal damage while you’re concentrating on a spell; if the target was concentrating, you heal for the damage dealt.
  • Psionic Overload – Add 1–4 psychic damage to your attacks every turn, at the cost of taking 1–4 psychic damage yourself each turn.
  • Transfuse Health / Perilous Stakes / Shield of Thralls – Trade your HP or tweak vulnerability and temp HP to create high‑risk, high‑reward plays.
  • Cull the Weak – When you drop an enemy below a threshold tied to your number of Illithid powers, they just die and nearby creatures take psychic damage.
  • Psionic Backlash – When enemies cast spells near you, you can react to deal psychic damage per spell level.
  • Late powers like Mind Blast , Black Hole , Displacer Beast Shape , Freecast , and Fly give you massive crowd control, mobility, and utility spikes.

Put simply: if you lean in, your party can become absurdly strong, especially on higher difficulties where the additional control and damage matter.

Story & Consequences: Is It “Bad” to Use Them?

This is where most players ask “what happens if you use Illithid powers in BG3” in the first place.

Short version

  • Using a few Illithid powers:
    • Gives strong abilities with minimal immediate downside.
    • May slightly change dialogue and how some characters comment on you.
  • Fully embracing the Illithid path (eating many tadpoles, taking the “astral‑touched” upgrades, leaning into Mind Flayer options):
    • Deepens your connection to the tadpole in cutscenes.
* Unlocks unique dialogue choices and power spikes.

* Sets up a specific endgame route where you can sacrifice your humanity to wield Mind Flayer power to defeat the Netherbrain.

Screen Rant and other guides note that a full Illithid route can lead to an ending where: you destroy the Netherbrain and save others, but you lose your humanity and memories as you embrace a Mind Flayer form. So the powers are less “game over bad” and more “trade your self for victory” if you go all in.

Most mainstream guides emphasize that using Illithid powers during the campaign doesn’t automatically lock you into a bad ending, but it does heavily color later choices and their tone.

Companions, Roleplay, and Morality

Using these powers isn’t just stats; it’s a roleplay statement about how far your character is willing to go.

  • Some companions react with unease or moral concern if you eagerly consume tadpoles, seeing it as corruption or temptation.
  • Others are more pragmatic or outright intrigued, pushing you toward using them as a path to power.
  • Dialogues often give you the option to solve situations with Illithid persuasion or intimidation instead of normal skill checks, which can feel very “wrong but effective.”

This tension is part of why “what happens if you use Illithid powers BG3” keeps showing up on forums and guides in 2023–2025: people don’t want to accidentally ruin their “heroic” run, but they also don’t want to miss out on strong abilities and unique scenes.

Pros and Cons in One Glance

[10][8][7] [9][8] [3][8][7] [3][8]
Using Illithid Powers Upsides Downsides
Light use (few powers) Nice combat boosts, extra dialogue options, no hard lock into a bad ending by itself.Some NPC/companion discomfort, subtle “corruption” flavor in story scenes.
Heavy use (many tadpoles + astral powers) Huge power spike, unique late‑game choices and scenes, very strong endgame toolkit.Pushes you toward a route where you may sacrifice humanity/memories for power, darker tone to your arc.

So… Should You Use Them?

Most modern guides land on: yes, you can safely use Illithid powers, especially if you want to see that side of the story and enjoy powerful builds. The “bad” part isn’t a secret Game Over, it’s a thematic choice about what your character is willing to become to save the world.

If you’re on a first, blind, “heroic” run and want to preserve your character’s humanity at all costs, you might:

  • Use only a few early powers,
  • Avoid fully evolving the tree and late astral upgrades,
  • Or save the full Mind Flayer path for a second, darker playthrough.

In other words: using Illithid powers in BG3 is a power–for–self tradeoff. The more you lean in, the more you risk winning the war while losing the person who fought it.

TL;DR: Using Illithid powers in BG3 gives you a powerful extra skill tree and cool dialogue options, doesn’t instantly ruin your run, but heavy use can lead to a darker, more Mind Flayer–centered ending where you give up your humanity for victory.

Information gathered from public forums or data available on the internet and portrayed here.