Yang runic oak 

Aster took a moment to try and discern how this place worked, the castle which was surrounding the giant tree, no, even the tree itself was of a bright yellow color.

Similar to the small yang rich land which surrounded the chain link, which was the place that gave birth to the immature Diamond Bone Orchid, everything here has been radiated by yang.

But the scale was on another level, also the yang in this place was different, instead of heat, the yang here was focused on life, which was probably related to that giant yellow tree, that wasn't covered by crystals unlike all the other trees.

The tree roots then guided them towards the castle, on the way Aster naturally looked for any traps but he couldn't find anything, so it was safe to assume the tree really wanted to reach a deal with them.