“The power they offer is incredible.”
And all they want in return is for us to find that that tree.
I imagine by now Beurghes has turned about full traitor and sided with the Nightborne, willing to expose and teach ancient druidic magics to their botanists in return for their own arcane knowledge. In accordance to the trade, Beurghes will call upon his own for what the Grand Magistrix wants destroyed, and with it incapacitate the resistance.