So by now, you've probably heard of Tenris Mirkblood, the Blood Elven vampire boss in Karazhan who is surprisingly generous with his loot, dropping a Vampire Batling for everyone in the raid as well as a very sweet axe by both the musical and weaponry related terms -- Although only one of those, unfortunately.
Tigole answered a few questions about this boss in a recent post on the forums. Tenris will only be around for about 10 days, which is why he's so generous with the bat pets, and the axe is the only other item on his loot table, if you don't count the Badges of Justice.
So what this means, first of all, is that if you haven't managed to get a group to go beat him down, you'll want to do it soon or lose your chance at a pretty cool pet and a pretty cool -- if rather weak -- novelty trinket. In addition, if you weren't lucky enough to win the roll on the Arcanite Ripper on your first try, it looks like you'll only have one more chance at it. Sacrifices to the gods of dice and/or the Gods of Metal, whichever you subscribe to, are recommended.
One other thing that's interesting to note is that 10 days, even starting from today and not from the first day Tenris appeared, doesn't bring us even close to the launch date of Wrath of the Lich King. This could suggest that the Zombie Plague will end sooner than we think, giving us some breathing room between then and the launch. Of course, it could also mean that Tenris will simply exit Karazhan, perhaps finally vanquished for good, perhaps to lead forth the armies of the Lich King on an assault against nearby Stormwind, bolstered by whatever dark powers he is researching or trying to harness in Karazhan.
Or Tigole could have just been giving a very ballpark figure off the top of his head, and we'll see Tenris around for quite a few weeks. Either way, it should be a whole lot of fun, and we'll see how it pans out. Be sure to keep tuned to WoW Insider for all the latest news on what's going on in the World of Zombiecraft!