Since it seems to be the newest trend, the Kawenu are gonna have to have come to Earth at one point in our history.
Many Kawenu used to be (before the Last Kawenu War) quite power mad.
One Kawenu in particular was even more power mad than any before, or after him.
The name of this Kawenu?
Huitzilopochtli.
Having been born with a rare genetic abnormality which made his skin color blue, like a Kawona, instead of the normal Kawenu green, he was ridiculed most of his life.
His dream was to prove he was as good as... no, better than any normal Kawenu.
One day he had had enough, and stole a standard fighter (with most of the crew still on-board) and set off in a random direction in space.
Because of Huitzilopochtli's extensive technical and combat knowledge, he was able to keep the crew at bay for an incredibly long time.
By the time the crew were able to regain control of the ship they were already far beyond any existing Kawenu starcharts.
During the chaos, many of the ships controll systems were heavily damaged, most unrepairable.
The crew found themselves hurtling out of control toward a small blue planet in the middle of nowhere.
After another fight with the remaining crew, witnessed by a large tribe of the planets native intelligent species, Huitzilopochtli saw the perfect opportunity to get the one thing he always wanted most, absolute power.
He became the ruler and most powerful god of this wandering tribe, and led them to where they would eventually build their vast empire.
The people who built this empire are known today as the Aztecs.
Aztec rendition of Huitzilopochtli:

Bronze Age Kawona (from page 1 of this topic):
http://en.wikipedia.org/wiki/HuitzilopochtliThe odd part about all this?
I totally didn't base the Kawona/Kawenu off this god when I started them, just the early Americas in general.
The similarity with this particular god was entirely coincidence.
I drew that Bronze Age Kawona a long time ago. I found out about that god and what he looks like less than 2 hours ago.
Maybe the Kawenu actually exist and really DID come to earth! *X-Files Theme Song*