Blizzard has released a new blog covering the Cross-Faction Guilds feature coming in Dragonflight Patch 10.1: Embers of Neltharion on May 2nd!
No longer will you have to wish your Horde heart could find a home with the amazing Alliance guild you just cleared a random raid with. Nor do you have to don a cheery Alliance front after wishing a fond farewell to some fantastic Horde heroes after a successful Heroic.We're blurring the faction line for guilds and allowing players to create and join same-realm guilds with their friends from the opposite faction when the Embers of Neltharion update arrives on May 2.Some things to remember with cross-faction guilds:Guild affiliation with the Alliance or Horde will depend on the faction of the Guild Leader, and guild achievements and vendors will still reflect the guild's primary faction.Guild members of the opposite faction will benefit from unlocked shared perks but cannot contribute to specific achievements. As an example, Alliance members of a Horde guild could not contribute progress towards the «Alliance Slayer» guild achievement.
Guild repairs and social conveniences, like shared chat, will be available to opposite-faction guild members. Players must be Battle.net friends or part of the same Battle.net community to invite or receive an invitation to an opposite-faction guild on the same realm.
Opposite-faction guildmates can only play communally inside instances; they'll still be considered Unfriendly to each other (or Hostile in War Mode) in the outdoor world. We look forward to you continuing your adventure through the Dragon Isles when Embers of Neltharion goes live on 3 May..
Read more on wowhead.com