Heartbreaker (10 player)

The actual text for the achievement is a typo here.

It's supposed to say "XT-002 Deconstructor slain".

Your quote is a possible referrence to Hitchhiker's Guide to the Galaxy, where they question authority figures.

Ok, so this is curious. A few days ago, during this year's Hallow's End holiday, my guild decided we were going to try for this achievement as our first Ulduar hard mode. On our first attempt, we succeeded in killing the heart and activating the hard mode, but failed to defeat the boss. It was late, so we called it a night and that was our only attempt of the evening. The next day, all ten of us that were involved in the killing of the heart received a letter in the mail, titled "Glory and Honor", from one named "Parthenia" which read as follows:

"Dear Champion,
Word of your achievements in Ulduar arrived by courier to my small home in Darkshire. My late husband was a great adventurer like yourself but met his demise at the hands of that mechanical monstrosity, XT-002. When word of his death reached me, my heart was broken. I now implore you to shatter the heart of that beast the way mine was shattered. Destroy his heart, champion, and songs of your glory shall spread throughout Azeroth!

For the Alliance!
--Widow Parthenia"

I searched Darkshire, and then wowhead for an NPC named "Parthenia", but returned no results. I thought it strange that I could find no evidence that anyone else had received this letter or even heard of Parthenia, but I just regarded it as one of those little things Blizzard implemented to add a tiny bit of incentive for killing XT's heart. Things got stranger later that week, however, we were successful in defeating XT after destorying his heart. Next day, we all received more mail from this mysterious widow. This new letter was titled "Vindication" and read as such:

"Praise be to the Light!

Your mighty deeds have not gone un-noticed. The retribution you wrought on my behalf has freed my once-vengeful spirit from this mortal plane so that I may be reunited with my beloved once more. For too long have I wandered in darkness bound by the strength of my grudge.

Thank you Champion.
And Happy Hallow's End!"

For all of us, the letter was accompanied by either a Voodoo Skull or a Haunted Herring. I found the ending of this letter most intriguing: "Happy Hallow's End!" This would suggest that these letters are only sent out when you perform the event during Hallow's End. But why is defeating XT on hard mode linked with this holiday? I thought it weird.