A character build is simply a your chosen play style and how you develop your character's stats and skills. A high dexterity, Explosive Arrow using archer is one type of build. An archer with stats spread out a bit more with either magic or melee weapons as a backup would different builds of the more general archer build.


As I mentioned in your other topic, you need to turn Amdusias human in order to defeat him. He can not be attacked in dragon form.

The librarian is looking for a book (that can be found on that level), which contains various transformation spells, one of which Amdusius used to become a dragon. When you bring him the book, he will give you the second volume, which contains the counter-spells. Reading that book from your inventory will cast the counter-spell, as long as you have the required ingredients.
The book can be found in the chamber with the bedrooms upstairs...
The book is in a locked chest downstairs, while the key is in the secret room upstairs - use a book in the bookcase in one of the rooms.

The ingredients can be found near the key to the chest, and in the room with Amdusias...
The vial of blood is in the secret room, and looks a bit like a candle at first glance. The scales are on the ground on the path to the blood alter.


To the far south west in Broken Valley you can follow a trail up to the fjords, and get around the starting section (a barrier prevents full access until you have the battle tower). I'd take out Amdusias first, then when the blocked hallway there is open I'd go check it out, but put off using the teleporer until visiting the fjords and getting to a new level (as I explained in your other topic about this).