Vashtunari

The Vashtunari are an alien race from High Crusade.

Physiology
Vashtunari had green hair and feathery antennae, and quite possible of compatibility with humans.

History
During the Englishemens' campaign to topple the Wersgorix Empire, Red John Hameward rescued a captive Vashtunari princess, who's people were about to be enslaved by the Wersgorix. The alien natives were grateful, but the Vashtunari's humanlikeness brought up a debate on whether prohibitions of Leviticus are applicable.

Source

 * The High Crusade by Poul Anderson