Sphinxes are creatures with the bodies of lions, feathery wings, and human-like heads. They are exceedingly rare, having been encountered only in Xen'drik.
The only known sphinx on Khorvaire is Flamewind, who was brought there from Xen'drik in 996 YK. She has refused to share anything about herself or her species, and she is immune to divination magic, so we know next to nothing about them.