I will keep posting the background story for Samuel in my posts until they catch up to the present. Some of it will continue to be cryptic, but you will either figure it for yourself or in second part of the story, where it is two hundred years into the future and the characters are seven years older. Haha, I assure you that Sam will not be like that!

You can definitely revise your current spirits, so that they function better within the stagger system, but they should remain pretty much the same if you don't change them for something else. You'd have to give me an example of how you would like to "level up" your skills, as it would be easier for me to answer the question! Around four skills/spirits is what each character can have that are 'combat oriented.'