that dosent in itself mean they are the key to the HAA - i am with Ant13 - it is CLEARLY Legion - the runes themselves are no longer Scourge/Vrykul on the HAA they are illidari/legion
that is why we havent found it more than likely tbh - everyone assumes Vrykul or Tauren but nope imo it has something to do with us making a Legion Deal or an Illidari (i.e. Altrius) that dosent seem to agree with hiding their knowledge
as well if one really looks looks at the HAA those runes are scattered at every illidari outpost