While I'm hoping each playable character, including Tav, has a special ending, I don't want to assume too much about how evil each has to be.
Players probably wouldn't be satisfied picking Gale, SH or Wyll... just to encounter railroading. It's a bit mean to do. D&D players are no doubt among the most critical roleplayers.
Of course, a predetermined ending /may/ be the most logical, but it's limiting. Larian seems too flashy in their style to sacrifice player choice. They're flashy enough that I have to wonder about physical marks of evil (tadpole use).
..., the five origin characters are just pawns.
gale -- want to become a god, this makes the power controls him, despite he is knowing the dangerous, someone(a god, or might be a devil) is easy give him a thrust into the power whirlpool.
wyll -- want to become a hero. he hopes people think that he is a hero, but he is violating the nature of a hero, he can do the betrayal to return other's give.
astarion -- want to replace his master, but he is going to do the things the same evil as his master.
shadowheart -- a puppet of shar, we know shar's plan has no good things, in the fact, this is going to be a great evil of some disaster purpose.
lae'zel -- her queen's order is absolute, this makes her achilles heel.
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only your custom character won't have the weaknesses. and be a X factor of the chess players(gods, devils and god-like beings).
