I understand that, when opening a skill, it’s 1/2 (round down) of the root stat, and also the same shade as the root stat (with essentially equivalent rules for multiple roots).
So… what happens when the root advances? Does it likewise advance all of the skills attached to it?
If so… how does that pan out? Do you just ensure the skill is at least the minimum it would be, if it were freshly opened? That’s my assumption.
Increasing a stat doesn’t affect any skills you’ve already opened. It does affect what new skills are opened at.
So, you burn a character with an Agility of B5, and pick up Sword, which opens at B2. At some point, your Agility increases to a B6. Your Sword stays where it is, but if you opened Axe after Agility advanced, it would open at B3.
Same thing with shade-shifting - it only affects stuff you learn after the shift, not the stuff you already know.