Sanguine

As far as I know sanguoine is not an adjective: it is the vocative from "Sanguis, sanguinis" a word that means "blood"

"Sanguine King of the Least."

I'm under the impression "Sanguine" could be a name of someone in this sentence, but it is impossible to say without a little more context.

I could not come up with a direct translation. Under "sanguine", my
trusty Cassell's dictionary said "see HOPEFUL." I did. Under hopeful, it
said "express by 'spes' or 'spero.'" The former is the noun "hope" and
the latter the verb "hope."

Based on this, I would translate "Sanguine king" as "Rex plenus spei"
and "Sanguine king of the least" as "Rex plenus spei minimorum".

Thanks!
Very helpful!

Happy to have helped!