I’m not sure if the plot thread ever went anywhere (I mostly liked 40k to read the lore in the codexes and buffalo buffalo buffalo buffalo buffalo this was years ago) but the Tau were kind of being propped up by the dark eldar who would frequently and seemingly benevolently swoop in to save them from various threats like tyranid invasions with some omanous price implied to be paid at a later time.
The Dark Eldar saved the Tau from a hive fleet for a ‘mere’ cultural exhange.
The Tau who accompanied the Dark Eldar to Commoragh were turned into Talos engines and the like, mutated horribly and tortured by Hommonculi.
The Tau have since learnt the difference between the craftworld Eldar and their debased kin. Something most Imperials don’t seem too interested in learning due to their extreme xenophobic brain washing.
I’m not sure if the plot thread ever went anywhere (I mostly liked 40k to read the lore in the codexes and buffalo buffalo buffalo buffalo buffalo this was years ago) but the Tau were kind of being propped up by the dark eldar who would frequently and seemingly benevolently swoop in to save them from various threats like tyranid invasions with some omanous price implied to be paid at a later time.
The Dark Eldar saved the Tau from a hive fleet for a ‘mere’ cultural exhange.
The Tau who accompanied the Dark Eldar to Commoragh were turned into Talos engines and the like, mutated horribly and tortured by Hommonculi.
The Tau have since learnt the difference between the craftworld Eldar and their debased kin. Something most Imperials don’t seem too interested in learning due to their extreme xenophobic brain washing.