Reddit mentions of The Younger Edda: Also Called Snorre's Edda; Or The Prose Edda

>the lower castes have to bow to them out of respect for the sacrifices they made.

But Kshatriyas still have to bow to Brahmans.

>The Kshatriya are described as being appointed by Brahma and other Hindu Gods as defenders of Earth

So does every other warrior caste or group in every other nation being appointed by gods and blah-blah

>Where Ksahtriyas actually thugs who raped and pillaged Indian villages

Yes - but it was a heroic deed back then. There were no 'Indian' though. Every nook and cranny has its own tribe. Also take into account that norm were quite different from a norm of modern ethics.

>Or are they genuinely heroic castes

They were victors, who wrote the history. In their history, they are genuinely heroic. Try to find an example of national epic in which its own heroes weren't noble (again, taking into account prevailing mores of the time).

>It draws parallels to medieval romances and Tokugawan haikus

True. Also, it parallels with vikings, condottieri, bogatyrs, pekhlevans, cossacks, Shaoling & Taoist warrior monks, Hussars etc. Almost every nation came thru that phase - when a special group of highly skilled warriors existed inside it. Usually it was during a period of feudal strife. Similar traits were a code of conduct, prowess in mano a mano combat and some artistic inclinations.

Sources

1. The Younger Edda
   
   
2. The Romance of the Three Kingdoms
   
   
3. Ilya of the Murom
   
   
4. Condottiere - Encyclopaedia Britannica