Hagatha's letter was a letter Graham found in the basement of Angelina's Antiques.
Once again, I put to you an invitation to join our illustrious community. Unsurprisingly, you have heard of its reputation through other channels. I personally encourage you to give it serious thought. We are not only interested in new membership from mages of the world. This invitation goes out to all who believe that, when the appointed time comes only the faithful will be rewarded. The rest of those poor, unenlightened fools will perish. All that is asked in return is complete allegiance to The Father. He has guided us from the beginning, and His Power is far older than most. Let me assure you that black would look simply charming on you, dear.
My gratitude goes out to you for your flattering assertion that I would make a fine ruler of Kolyma. What a shame that the former ruler has lost all interest in his homeland. I cannot blame him however. The Change struck him quite hard.
To answer your earlier question, yes I have acquired a nightingale. They are most uncommon in this region, and yes, I am quite sure that it is the final ingredient required to complete my youth potion. As much as I would like to share it with you, I am afraid that a single nightingale will provide only enough solution for one person. In any event, I shall, of course, pay you a visit the moment the youth potion takes effect.