Can you convince Astarion to become half-illithid?

Yes, it is possible to convince Astarion to undergo a half-illithid transformation in Baldur's Gate 3 under specific circumstances and through a particular method.

The Path to Astarion's Transformation

Convincing Astarion to embrace a partial illithid nature is not a straightforward task and depends on several critical factors during your playthrough. It is a unique opportunity that arises if certain conditions are met regarding both the player character and Astarion's personal story arc.

Prerequisites for Persuasion

For the option to convince Astarion to appear, two main conditions must be satisfied:

• Player's Own Transformation: The player character must have already embraced their own partial illithid powers, signifying their willingness to delve into this new form.
• Astarion's Quest Status: Astarion's personal questline, specifically concerning his desire for Ascension (or its alternative resolutions), must not yet be resolved. This interaction typically occurs before his ultimate decision regarding Cazador.

The Coercion Method

If these prerequisites are met, the persuasion process involves a direct mental appeal:

1. Initiate Dialogue: During a relevant conversation or critical juncture in Astarion's story, an option related to transformation will emerge.
2. Mental Temptation: As a half-illithid, you gain access to a unique dialogue choice that allows you to use your new form as a tempting example. This option often appears as [WISDOM] Enter his mind, tempt him with the wonders of your new-found form. It is labeled as part of the "[Embrace Your Potential]" interaction, suggesting you are showcasing the benefits of your shared, evolving power.
3. Skill Check: Successfully influencing Astarion requires passing a Wisdom skill check with a Difficulty Class (DC) of 15. Succeeding in this check will lead him to consider and ultimately accept the half-illithid transformation.

This interaction is a testament to the influence your character can wield over companions, especially when sharing a similar transformative path.