upgrade rage skills, luck or something else untold?

[kemydes]

well, all the previous post that i have read about winning in impossible with no losses or at least very easy fight, it seems you have always the right rage skill ???? HOW could you do that ??? i have had never get the choice to upgrade time back for example or at least the range of target, with sleem i often get the poisonous bite!! instead of the toxic or glot armor and i dont speak about zerok with his wall or the falling stone so i wander how you could get what is really good ? is there a path to follow in the upgrade or its only luck?