You said it was an outside zone and High Keep is actually an indoor one, so that threw me and why I didn't ask about it.
The city zone designation threw me. I had narrowed it down to the Arena, which didn't have an NPC that fit the description. I could accept HK being 'outdoor' because I remember being able to have SoW cast on me there. I just thought of it as a city zone because I could also get bound there. I though that maybe it was Everfrost in one of the caves, because it's an outdoor zone, but the NPC I was looking for might have been 'inside' instead of outside.