Valia Isles (Shard Ne'Vaal Supplement)

The floating islands in the sky are nearly invisible to any who are not directly standing on it. They are known to appear only around once a year, peeking out in the canopy by the clouds. Birds and other simple animals do not seem to be able to access or even sense its presence.
These sky isles are named after the goddess Valia, who was lost in the Gorge. It is said these are remnants of her Elysium, a sanctuary for heroes and valiant warriors. Her sister He'Nth has since taken up stewardship of the lands and upkeeps them. At first, they seem too small to have anything on them. But upon getting closer, and touching ground, one becomes immediately aware that the entire island is basically a maze and coliseum.