Midnight Mysteries - Who was accessing Sev's account after midnight?

Sev said his goodnights after PvP just before midnight, and I went off to do challenge modes.  At about 1-130am, his account logged on and off.  A few times. Aza was on, and I said that it was a bit odd because Sev doesn't usually get back online after he gets offline.  It was very suspicious - like hacker activity.

"I thought Sev went to bed already," I said to Aza.

"He did," said Aza.  "Maybe you should call him..."

"But it's 1am, I can't, his brother will kill me," I replied.

Instead, I demoted all of his toons to hibernating.  His account logged in again and I whispered him.

To my surprise a message popped up, saying a GM would like to speak to me. My first thought was "Wow, they want to notify the guild leader of suspicious activity on an account in their guild?  That's new!"

It turned out that the GM was accessing Sev's account to give him an achievement/title that he was missing. Of course, I knew exactly which one it was.

And so, the mystery of Sev's account was solved.  And now we all have our Vanquisher titles!