Heart container

An obvious reference to the Legend of Zelda series' heart containers.

Directions
From the Nexus waypoint:
 * 1) Left
 * 2) Left
 * 3) Left
 * Up
 * 1) Walk behind the pillars, going up
 * 2) When you can't go up any more, go right along an invisible path.

The chest is in mid-air.