Originally Posted by Silver/
It has nothing to do with the narrative or programming. It's that Halsin's level is too high for an act 1 party. Druids have ranks which are associated with levels, so they can't just lower it either and remain coherent within the lore.

I think they have sort of turned "Archdruid" into a vague term. He is not a level 20 at any point: a level 4 player druid is just as strong as he is when escaping the Goblin Camp. Kagha is also an "Archdruid."