Brawler's Guild - Legion

With the Legion expansion there is a new Brawler's Guild, which was released in patch 7.1.5, and all previous achievements have moved to the legacy tab.  As with Brawler's Guild in the previous expansions you move through the ranks from 1 to 8 fighting four brawls in each rank.  There is also two new fight modes random brawl and Rumble.

How it works is this, anyone can enter the special Brawler's Guild areas which are located in the Valley of Honor in Orgrimmar for horde or by the Deeprun Tram in Stormwind for alliance.  However, in order to fight first you need a brawlers invitation.  Either Blood-Soaked Invitation, which drops from emissary bags, completing dungeons or from the elite vrykul in Sheild's Rest, Stormheim or Brawler's Pass, which can be gifted or bought from the auction house.  The invitation is account wide and once you have it your characters can queue for brawls and will face the enemies in order depending on your rank. You cannot skip a brawl and so can only move on once you have defeated them.  While waiting for your turn you can watch and cheer on the other players.

The achievement for getting the invitation to the Brawler's Guild is The First Rule of Brawler’s Guild.  There are also some new rank achievements to collect.  The first is after you win your first brawl You Are Not Your $#*@! Legplates. The second The Second Rule of Brawler’s Guild is when you reach rank 4 and you will also receive a brawler's pass in the mail to give to a friend.  The third is King of the Guild and is awarded for reaching rank 8.  Rank 8 also awards the title Brawler Your Name.

At rank 3 you are able to purchase a new pet Tylarr Gronnden from Paul North who is situated inside the Brawler's Guild opposite the entrance (horde).

At rank 8 you can purchase the new mount Brawler's Burly Basilix.  Paul also sells shirts, the heirloom fist weapon and pet Clock'em from the previous expansions as well as brawl specific potions which are slightly better than normal potions but can only be used in the Brawler's Guild.

There is also a new currency, brawler's gold which is awarded when you win a brawl in the brawlers purse, roughly about 90 - 100g per brawl in rank leveling and around 250g for a random brawl.  This currency can be used to purchase some helpful or different mode items.  You can purchase the following from Tiana Nevermorn at the back right hand side of the arena (horde):

Blood-Soaked Angel Figurine - this puts a grave yard inside the brawler's guild for the next 30 minutes so people can res inside if they are defeated instead of having to run back in.

Bag of Chipped Dice - this gives players the opportunity to queue for random brawl mode for the next 30 minutes.

Brawler's Potion Dispenser - this dispenses free potions to all players for the next 30 minutes.
High Roller's Contract - This enables a game of chance for the next 30 minutes during which time you can bet on who will wins the brawls hero or monster.

Various Rumble Cards - which will start specific rumbles.

You are also awarded 1g for every fight that happens for which you are present win or lose.  There is an achievement for collecting 20,000 Brawler's Gold,You Are Not the Contents of Your Wallet .

There is a really good guide on Wowhead which gives info on all the rank and random fights Wowhead Legion Brawler's Guild Guide.

Happy Brawling!