One of the YOutubers, eitehr Fextra or WOlfHeart, said, that the more tadpoles you insert the more dead your brain tissue will look, so I'm pretty sure, putting tadpoles into your brain, is exactly, what they mean.
I will certainly hope so. It would cheapen the plot so much if there are no repercussions. Questing for power must always come at a cost.
And frankly, I love this idea. "I'm a holy paladin on my righteous Quest! As a servant of Torm I swear that no evil shall....Oh. Wow. Well. Double Crit chance does smell tasty...Maybe just this one."