Now, the overall story line of this anime is semi-original. The red-heads and dirty-blondes and such are somewhere in the middle. The 'Dhalites' or 'Harijan' of this caste would be the dark-skinned, brunette, and brown-eyed men from the so-called 'slums'. This masculine society is separated into a caste system by hair and eye colour where, as is to be expected, the 'Brahman' and the 'Kshatriya' are usually blonde-headed, fair skinned, and pale eyed.
The story line is sci-fi in nature_centering on a planet which consists almost entirely of a male population and over lorded by a super-computer by the name of 'Jupiter'. Okay, Ai no Kusabi is one of the better examples of Yaoi that I've seen thus far.