I think it refers to the void or the Old Gods, not the Legion.
I'd rather it didn't given that I despise Anduin as an annoying pacifist, but knowing Blizzard it seems the most likely direction.
Do no harm, but take no shit.
I wanted to kill Anduin as Horde so bad in the Temple of the White Tiger and the Krasarang quests...
Helping an Alliance prince as Horde is just wrong.