Or ...
Level is just game mechanic that have litterally nothing to do with story told and we are just connecting dots that dont belong together.
Also im quite sure that Jaheira dont have any brainbug, in scene we have seen on PFH she didnt sense Swens character, nor that Flaming Fist dude ... the tadpole she had in jar didnt react on her in any way ... Swens character didnt have any option to sense her either ...
Basically all we know abouther is that she sits on her ass in some sort of camp ...
While Minsc was kidnapped ...
So it on the contrary seems lukely that she is actually NOT tadpoled.
I still dont understand why cant we change Race for our hirelings.
Lets us play Githyanki as racist as they trully are!
