Dun Scaith is a 24-player alliance raid for level 60 characters introduced in The Far Edge of Fate (Part I), patch 3.5 of Final Fantasy XIV.
It is the third and final installment in the series of Mhachi raids that began with The Void Ark and continued through The Weeping City of Mhach. It requires an item level of at least 235 to enter, and the three parties of the alliance are in what has been standard alliance raid configuration since Syrcus Tower in A Realm Reborn: one tank, two healers, five DPS.
The raid drops item level 260 gear (which, at the time of writing, players are limited to acquiring one piece of per week) along with the Paladin glamour weapon Blood Sword, a Wind-Up Scathach minion, a Diabolos Hollow Triple Triad card, and Void Matter, an item needed to craft a few Dun Scaith-related housing items.
Note to visitors: This guide is a little out of date now thanks to a few changes to Dun Scaith, but the strategies for the main bosses still stand.