Xenoblade Chronicles/Ether Mine

If you made it this far, check your equipment and don't forget to do sidequests and upgrade your arts through books that you need to buy. This is pretty much the size of Colony 6 underneath, while the top is pretty much awful, which is why you can't get in yet.

Saving Otharon
Start off by following the Mechon's until you reach a cavern area featuring rails, metal, and lights. When you reach the cavern, a cutscene ensues that focuses on Sharla, Otharon, and the mystery behind Gadolt. Shulk encounters a vision in which Otharon is dying in an ether river which will be revealed at the end of this level. He leaves you after some miscommunication.

Going down
This isn't easy, but start off by going to the north end to unlock the door on the south side. Then follow the trail through elevators and moving platforms that goes up and down and along sloping caverns. Take down as many Mechon as you can to gather experience. Eventually, after about 5 levels down, you'll reach the elevator which takes you even further down to the centre.

Xord's ground battle
It may sound tough unless you already finished the available sidequests prior to this event. After the cutscene, if you're controlling Shulk, enchant your teammates with your Monado since their weapons don't have any effect on the metal. As usual if you're following the tutorial so far, break follow by topple then daze anyone around you. Once Xord's health is about half, a dramatic cutscene plays out the moment almost like the vision beforehand. Otharon's life is about to end when Reyn comes to save him in the nick of time.

Xord's elevator battle
Now go back to the elevator and get to the last section via moving circular platform (watch out for the wall!). Reach the freight elevator and go up. It stops for some reason: Xord is back, having survived the ether river. You should know what to do at this point since there isn't any other Mechon's distracting you. Once you defeat him, a cutscene shows that Xord is impressed that Shulk defeated him without unleashing the Monado's true power. Then he falls to his death allowing the freight elevator to move again.

Dunban's back and more visions coming
You're on the other side of Colony 6. Well if you think it's over, think not. More Mechon's came and Metal Face comes down as well. Dunban makes his entrance and Dickson comes along as well. Also for the first time, a Telethia saves the current team from Metal Face's blast. For the final battle, you can choose between Shulk, Reyn, Sharla, and Dunban as Dickson is not exactly ideal for this.

A cutscene that follows shows Shulk trying really hard to cut his Monado down while experiencing more visions. His vision shows they're on top of a tower, the mysterious silver hair girl with the old man, an old bearded giant, Monado's extended power that knocks Metal Face hard and a silver faced Mechon with a girl inside. Take note as these will play out exactly as you see it far later on. Metal Face and his goons leaves you for another time. The clues to the vision is simply from Dickson: Prison Island and the civilisation that last longer than Homs is the High Entia because of the Telethia. Most intriguing is the silver hair Homs who'll reveal himself later on. Be prepared to meet more people on your journey with one obstacle: Satorl Marsh.