Creatures of Ava

For this, you will need to unlock every single node on the Skill Tree tab. This means every single Attribute, Tool, Nafitar, Spell, and Story node. You will need to find the collectibles in each region, and complete most if not all of the secondary quests, along with filling out the Avapedia, in order to obtain enough skill points.

For me personally, learning the "Song of Sand" in the final region, the Dunes, as part of the main story was the last thing I needed and the achievement unlocked. In the end, the skill tree will look like this:



Even after this, I still earned a few extra skill points. So there is a little wiggle room, but not much.