Bizmo and Boss Bazzelflange, leaders of the Brawler's Guilds
The first rule of brawls is you don’t talk about the brawls. The second rule...[1]
The Brawler's Guild is an organization that arranges one on one battles between willing combatants, captured monsters, and other participants in gladiatorial combat. Being a neutral organization, members of the Horde and Alliance are both allowed to enter, rising through the Brawler's Guild ranks with more wins. Prizes are awarded at higher ranks. The fights are all solo PvE matches in which the players must adapt and use different strategies depending on which opponent they are currently facing, making the Brawler's Guild one of the most challenging PvE activities a player can attempt on their own.
On 27 November, patch 5.1 and the Brawler's Guild went live, and Community ManagerNethaera again confirmed how invites will be obtained. "Entry into the brawler’s guild is by invitation only. Invitations can be found on the Black Market Auction House, by invitation from somebody within the guild, and occasionally as drops from certain Horde and Alliance NPCs."[2][3]
Upon reaching Rank 7 with Bizmo's Brawlpub or Brawl'gar Arena players will receive one [Brawler's Pass] (Alliance / Horde) in the mail. The pass can be traded and sold on the Auction House to other players and is the only other means to gain access to the Brawler's Guild.
Using either invite, the account is flagged to join the Brawler's Guild, giving all characters on a player's account access to the guild. Future expansions will not get rid of this membership. Once you're in, you're in for life!
A nice little bonus is that once you reach rank 8, this gives you the right to go into the area for VIPs only.
Speak to any bouncer or look at the Queued for Brawl buff tooltip to see your spot in line. Then, wait until the queue pops - a boss emote will display warning that the next turn is the adventurer's:
You are next in line!
There will be no warning upon getting teleported to the arena floor. The fight lasts two minutes before the arena itself will kill adventurers who take too long.
Queue system
The queue system is built on a first come, first serve basis, with one exception: you will be placed one spot behind for your first fight for the day (current fight, next fight, and your fight). This rule is applied to all your eligible characters individually, not to your account.
After the match
Winners will receive a [Brawler's Purse] and 250 reputation with the Brawler's Guild.
Normally, challengers will only fight the next higher-ranked gladiator until it is defeated or the challenger throws in the towel, but the addition of Challenge Cards gives challengers the opportunity to relive earlier fights. For the ranked fights, defeating a gladiator will unlock that gladiator's challenge card. There are also rare challenge cards, unlocked upon gaining higher ranks and completing quests that are started by items found in the world.
The Brawler's Guild was on hiatus between the launch of Patch 7.0.3 before Legion in preparation "for the next big thing".[6] The guild returned in Patch 7.1.5.
As part of keeping the Brawler's Guild fresh, Patch 6.0.2 retuned the fights for level 100 players, putting an end to the first season of fights. When players reach level 100 they will find that their ranks have been reset to one and the fights have been changed around, with some bosses going away from the rank rotation completely and becoming Challenge Card fights, making a max of eight ranks again. For example, Bruce will now be a Rank 5 fight and Hexos is removed. Players will also find new achievements for reaching the higher ranks again, the old ones being moved to the new Legacy achievements tab.[7]
Legacy fights are those that were part of Season 1, but were removed and made available only through challenge cards.
The concept of the Brawler's Guild appears to be loosely inspired by the film Fight Club. In particular, the introduction lines "The first rule of brawls is you don’t talk about brawls." and "If this is your first night at Brawler's Guild, you have to fight." are taken almost verbatim from the film. The developers have stated that the "Fight Club vibe" was an intended design aspect.[8]
Invitation to the Brawler's Guild was initially extremely limited, with invites only available as rare drops or from the Black Market Auction House. Part of the reason for this design was to reduce the rate at which players were able to access the Guild, due to concerns about server stability and the quality of the play experience with very large numbers of players involved. Knowing that the feature was eagerly anticipated, the developers designed the invitation system to allow players to "trickle into" the new content, "a little bit more slowly, a little bit more elegantly".[8]Tom Chilton described the Brawler's Guild design as "a pretty heavy-handed method" of achieving this, although its secondary effect of initially making entry to the guild feel more selective and restricted was considered to be helpful in establishing the Guild's "Fight Club vibe".[8]
According to Ion Hazzikostas' speech at the BlizzCon 2016 What's Next Panel, the Brawler's Guild is "100% non-canon".
As of patch 5.1, the Deeprun Tram is also the home to the Brawler's Guild for the Alliance, which is located on the Stormwind side of the tram.
Disruptron Mk. 3R-Alpha's attacks will no longer sometimes strike spectators in the Brawl'gar Arena. His attacks will now properly strike opponents standing on the grates in this arena.
Dark Summoner's health has been reduced by 10%, and his damage reduced by 35%.
Certain short-term buffs, such as [Bloodlust], are now cleared when entering the Brawler's Arena. Long term effects, such as [Heart of the Wild], will persist.
^WarcraftDevs; opinionatedpup 2016-04-22. WarcraftDevs on Twitter. Twitter. Archived from the original on 2016-05-04. Retrieved on 2016-05-04. “The Brawler’s Guilds are going on hiatus. They said something about “preparing for the next big thing”.”
World of Warcraft Community Site Brawler's Guild Updates
Icy Veins Brawler's Guild Guide
[Blood-Soaked Invitation], which is Bind on Pickup, can be found when you complete Legion dungeons or open Emissary chests.[4]
[Brawler's Pass] (Alliance / Horde) in the mail. The pass can be traded and sold on the Auction House to other players and is the only other means to gain access to the Brawler's Guild.
Yes, sign me up for a fight!
[Brawler's Purse] and 250 reputation with the Brawler's Guild.
[100] A Knockoff Grumplefloot & 
[Brawler's Ancient Healing Potion]
[Brawler's Potion of Prolonged Power]
[Clock'em]
[Tylarr Gronnden]
[Pit Fighter's Punching Ring]
[Gemcutter Module: Mastery]
[Brawler's Razor Claws]
[Brawler's Burly Basilisk]
[Bottle Service (Season 2)]
[Brawlin' and Shot Callin' (Season 1)]
Bizmo's Brawlpub/
Brawl'gar Arena during the Pandaria campaign.
[Collect Your Deck (Season 2)]
[Haters Gonna Hate (Season 2)]
[Having a Brawl (Season 1)]
[I'm Your Number One Fan (Season 2)]
[I've Got the Biggest Brawls of Them All (Season 1)]
[Rabble Rabble Rabble (Season 2)]
[The First Rule of Brawler's Guild (Season 2)]
[The Second Rule of Brawler's Guild (Season 1)]
[You Are Not Your $#*@! Legplates (Season 1)]
[Brawler's Gold] and 
[Bloodlust], are now cleared when entering the Brawler's Arena. Long term effects, such as 
[Heart of the Wild], will persist.