Creatures of Ava

EASILY MISSABLE

This Achievement requires you to find a Golden Figure of a Ran. The T-Rex style creature. There are 3 Figures in the game each of which belong to each biome; Jungle, Marsh, and Dunes. There is not one in the Grasslands this is were the Easter Egg is. You have to get all three in one playthrough since you cannot go back to biomes. Also percentage of the game does not matter you can speed run this.

Jungle Biome

Marsh Biome

Dune Biome

Grasslands Biome

I'm not going to spoil the Easter Egg, so enjoy.
If this is your last achievement for the game reloading a save may pop the "Platinum" achievement.

To unlock the underground hall you will need to take a picture of three T Rex Statues in each of the other 3 biomes located in the game. (You cannot fast travel back to biomes after you have completed them).

Statue 1 Nari Jungle - Parent Tree Gate
Statue 2 Maruba Swamp - Lake Temporary Station
Station 3 Antar Dunes - Near West Statue

Once you take pictures of all three fast travel back to the grasslands and the underground hall is located in the main city in what used to be a creek/river that ran through it. You can step on the elevator to take down to the secret hall.