Notes:

1. Level 10 skills are not upgradeable.
2. Not yet sure about level 12 skills.
3. Everything is hidden under the toggled menu in case you want to avoid spoilers.

Click on arrows.

Paths (a little bit outdated)

Ranger (Daggers)

Brute (Maces)

Swordsman

Warrior (Axes)

Archer

Spearman