Both of you made good points. I think that two distinct evil paths are needed. One following the absolute for its promise of power and one that does not involve giving the parasite more power.
As for the latter option the Goblins are the wrong allies. For that to work the player would need to discover at least a hint at their capability to halt the transformation.
Blindly trusting conflicting visions does not seem to be a path that selfish evil characters would follow. I assume that the player character does not wish to tear apart the love of his dreams so the dialog option indicates the tadpole wishing to fight its abuser (the absolute).
As it stands now the choice to side with the goblins looks insane. Give the player a reason to assume that the absolute will not let him/her turn into a mindflayer.
Did the other true souls get 'their' tadpoles by being abducted or did they bargain and volunteer?

I sometimes use thought experiments. I don't necessarily believe in every idea I post for discussion on this forum