GuildOx reports that Paragon, from the European Lightning's Blade realm, has defeated the Lich King and acquired the Frozen Throne achievement. While well-known guild Ensidia had defeated him yesterday on 25-man difficulty, they also employed some dubious techniques to win and later paid the price for it by having their loot and achievements removed.
Paragon, on the other hand, appears to have completed the encounter in an exploit-free manner and, according to MMO-Champion's Boubouille, did it on their first try. Congratulations go out to Paragon on their clean kill. Now let's see some of those heroic achievements!