What could this mean? - 40k Tau Lore

I think these are some good theories! What are your thoughts? Tau + Dark Angels super = super legion!!!! #warhammer #warhammer40k #warhammer40000 Warhammer 40k, Warhammer, Arks of Omen, Tau, Tau Empire, Tau lore, Tau Farsight, Commander Farsight, Dark Angels