Yes, you can absolutely convince Astarion not to ascend in Baldur's Gate 3. This is a significant decision point in his personal questline, offering a different path for his character.
How to Persuade Astarion
During the climactic confrontation with Cazador Szarr, when Astarion has the opportunity to complete the vampiric ascension ritual, you will be given the option to intervene. To convince him to forgo the ritual, you must pass a Persuasion check.
Succeeding in this check leads to several key outcomes:
- Cazador's Demise: Astarion will choose not to go through with the ritual and instead simply kills Cazador. This provides him with closure without sacrificing thousands of souls.
- A More Benevolent Path: This decision shapes Astarion into a more "good" and benevolent character. He moves away from seeking absolute power and focuses on his own freedom and the well-being of the companion he has become.
- Release of Spawn: The thousands of vampire spawn trapped in Cazador's prison are not sacrificed in the ritual. Instead, they are released. This decision has further implications for their fate, which Astarion will grapple with.
Choosing to persuade Astarion requires understanding his trauma and his desire for freedom from Cazador's influence, but steering him away from the cycle of abuse and power that he almost perpetuates. It allows him to break free from his past in a healthier, less destructive manner.
