Interesting choice, to go after Stephen. Was it ever confirmed he/she had investigative abilities, or did we just assume this was the case because of her role? This must be the reason to go after Stephen. NKing any other person at least gave you the chance to kill two players: if you got lucky and killed a player who knew too much, (s)he would be ineligible to replace the modkill.

Now the question is: what have we learned from this?
- FT really knew what Stephen's role was and was truthful about it. Did he ever explain how he knows?
- The manner of her dead indicates a huge object, with great strength, power or speed, being used to destroy several buildings. Could this have been a ram (like on Day one)? I must say it more than likely feels like a Troll has been out playing. Or maybe, seeing the words on the wall, this was the Hogfather's sled crashing into the buildings? (That's the Discworld equivalent of Santa Claus: "He wears a red, fur-lined cloak, and rides a sleigh pulled by four wild boars (or, in modern portrayals, cute pink piggies), Gouger, Rooter, Tusker and Snouter.") The Hogfather sounds like a logical character to have in this game.
(NB: if the Hogfather is a character, we may also have Death in here. That seems like a prime Survivor role. Although it would bring havoc in the world if Death is dead. Which sounds perfectly Discworldian).
- Stephen had several win conditions, some of which he may not even have known. That also implies we may have more win conditions we don't know (yet).
- The last line of the Flavor text: "Her death greatly saddens those of Uberwald, the Undead Community as a whole, and the City Watch." Can we read that as "groups" in the game? It doesn't seem like a stretch, if Stephen had four win conditions, that he was a member of more than one group at the same time. He could Night Talk with "some members", so that could be within one of these groups.
- And finally, the big one: Stephen had Night Kill ability. That, and the previous point, seriously puts turns my attention back towards the group of Undead.

The only reason I'm not voting against Yuna right away, is because it's obvious that she wouldn't have killed a team mate. After all: if she had NK herself, she could just have waited to see who got killed and likely could have gotten that person as a replacement. That means someone else likely did it.

I say it's time for a Hypocop at the very least. And can we get some info from Yuna whether NK is normal Vampire ability?