Riftwings are drawn to splinters and rifts. They feed off their energy and grow larger the closer they live to a portal. The Chaos Legion uses them as a means to locate rifts. In war, they are utilized as scouts, providing valuable information and as a way to harass/distract enemy forces, thereby slowing them down.
The sky over the battlefield was suddenly filled with an onslaught of arrows. Armored archers fired all at once, aiming for the creatures in the sky. The Riftwings of the Chaos Legion.
But as the arrows neared their targets, the Riftwings flapped their wings rapidly. A surge of wind kicked up, sending the arrows wide. Several of the weapons spun out of control, impaling the archers on the ground. Killed by their own attacks.
The screams began as the Riftwings dove down, following the path of the arrows. Descending on the corpses, it was a feast of blood and flesh.
Reference: Splinterlands.com