Ok before I start, this is not some sort of OMG WORLD FIRST thread. We were a couple of friends who started out by 5 manning the weekly and wanted to see how much content actually was 5 manable. It turned out; alot.
THIS IS NOT HARD.
We didn't minmax by changing people out. We ran with the same 5 ppl who killed ignis all the way through ulduar, toc and ICC. The only change there was, was our druid speccing between feral and moonkin.
We didn't have amazing gear. A part from myself (in quite decent ICC hardmode gear), the tank and shadow priest were in 264 gear, the mage was in a mix of 251 and 264 gear, and our moonkin was in a mix of 264 pve gear and wrathful pvp gear. This is our players:
Moonkin: http://eu.wowarmory.com/character-sh...riss&cn=Tjikko
Mage: http://eu.wowarmory.com/character-sh...&cn=Z%C3%A5nna
Feral Druid: http://eu.wowarmory.com/character-sh...meriss&cn=Tyla
Shadow priest: http://eu.wowarmory.com/character-sh...riss&cn=Koxxie
Resto druid: http://eu.wowarmory.com/character-sh...&cn=Nigeldruid
About our pve experience:
Me and the tank played (tank still does) in a top50 world guild on a different server. This is his alt, his main is a mage.
The Shadow Priest has decent PvE experienced, but hasn't killed LK heroic, Yogg0 etc. Kinda standard 11/12 kinda a guy.
The moonkin had seen the fight once before, however he got carried by a friends guild through a normal guild, and didn't understand what was actually going on.
The mage hadn't gotten past p1, let alone killed it.
A link to Tjikko and Zånna getting their achievements for 10man (and Zånna getting Ashen Verdict):
http://img269.imageshack.us/img269/1...0910185724.jpg
All in all this means that run with a group of people in full 277 gear and with a better setup, you'll be able to 4 man this, perhaps even 3 man. Therefore I acknowledge this to not be a huge feat for the greater public, however it's a feat for us (as two people got their kingslayer title this way!). Should this be a world first, it'll only be due to lack of anyone else doing it.
Videos of the Lich King Kill:
Part one: http://www.youtube.com/watch?v=b67YCceBDQo
Part two: http://www.youtube.com/user/sualitu#p/u/0/6gfS8CTcO8k
PS I have videos of Putricide, BQL, Blood Council and Sindragosa, however the quality of those ain't great. I can post them on request.