Borderlands 2 Tiny Tina's Assault On Dragon's Keep Walkthrough Part 10 – A Game of Games: Outer Dragon's Keep

Once in Horizon's End turn to the left, West, and take off down the walkway.  You have numerous Squires to deal with, a Knight or two and a Purple Dragon. Approach the Western end of it and likely a Badass Archer will appear and join into the fight. After they all lie in ruin head to the South and into the “Hall of Hyperion”.

Just inside the hall you can see a Fountain of Blood. Around it you will find various shrines you can play Eridium to for boosts. Fight your way through the various Knights and Archers. When the Archers appear you need to work quickly as there are 2 on each side and they have a good rate of fire. There is likely one Badass in the group so find him quickly. As the fight wears on expect a few more knights to join in. The good news is this  close to the end.  The final round has a Badass Knight coming at you with a few underlings as backup. After them come some Sorcerers for you to deal with. Kill them off and the way forward will open up for you. The gate at the Southern end of the Fountain Chamber will open and the door beyond it opens.

Just behind the door you will find more Knights to deal with. The good news is it is a much smaller group. They are still knight and armored foes. Just through the door you will find 2 Vending Machines. Clear out your stash and restock on ammo. After that just drop down over to the ledge to the West. You will find the Handsome Bridge which leads to the Dragon's Keep. The Handsome Sorcerer is setting up  his camcorder to watch the fight between you and the dragon.

Handsome Dragon
The dragon will fly above you and spit down fireballs on you initially. Just move away from where they will impact to avoid the worst of the damage. It will largely just fly circles around the bridge that you are fighting on. After a while in the fight Tina will summon up Roland to help you in the fight. Be careful moving around on the bridge because it is remarkably easy to fall off. For the first part of the fight just expect the dragon to fly around and either spit fireballs at the bridge or breath flame across it. As the fight where on it will also sweep across the bridge and do its fire breathing where you are. It will move just the same throughout. The Handsome Sorcerer will take with Smokey, The Handsome Dragon as you wear it down to the Quarter marks (¾, ½, ¼). He will get more vocal as The Handsome Dragon gets closer to deal, first telling it to retreat then to just kill the Adventurers already.

Kill the dragon and fireworks will go off as rewards rain down on the bridge. Grab what you want and head for the far end of the bridge. From there just go inside to the Lair of Infinite Agony.