Unfortunately, I believe that book will play a heavy role in Astarion's quest, or at the minimum... What happens to his alignment later. If he can master his vampirism, he will not need the tadpole anymore. Without that, I'm not sure there's a good ending for Astarion.
Be enslaved to the tadpole (very bad), become a fully fledged vampire overlord (worrying), or (near?) cure it altogether? One path seems more consistent with magic mirror option 1 than the others. However, suspiciously, a real vampire could never wish for something as simple as magic mirror option 1 (see his homeland again). Conincidence? Either vampires are not forced to be greedy and evil anymore, against 5e... or something happened to that vampirism.
Every companion (save Lae'Zel) has a tadpole ending, a good ending and a bad ending by that mirror. Somewhere the paths diverge.
Last edited by Silver/; 17/01/23 12:37 AM. Reason: Addition
