Our Xenoblade Chronicles guide features a comprehensive walkthrough and additional info on the endless amount of optional content in the game.
Walkthrough: Colony 9
When the cutscene concludes, you are left in control of Fiora, Dunbanís sister. At his suggestion, you have to find Shulk. Head towards the Residential District (west from the Military Dist.) and follow your goal marker to the area known as Outlook Park. When you arrive, you'll learn a little more about Fiora, Shulk, and Dunban.
With that complete, head back to the Weapons Development Lab. After your arrival, you'll eventually regain control of Reyn and Shulk. Youíll also get the chance to level up your Arts at this point. You should take the time to examine your Skill Trees at the moment as well. Skills boost certain stats or abilities and can be shared between characters, though sharing does have its limitations.
Tephra Hill / Tephra Cave
Your next goal is Tephra Hill. To get there, you need to take the alternate path back at the fork near the entrance of Colony 9. On your way, youíll reach a point where the path bends northwest. There is a hill on the northern wall. Explore the hill a bit and youíll see your first Unique Monster UM, Evil Rhangot. I advise that you avoid encountering the Rhangot for now, as itís likely youíll lose and respawn at the entrance to Colony 9. For more info on Unique Monsters, take a look at our handy sub-guide.
Continue down the path. Once you reach the Tephra Cave Entrance, Fiora will rejoin your party. Head into the cave, advancing towards the Ether reserves that lie in wait. As you make your way through the cave youíll come across a pit (The Caterpile Nest) with three Eater Caterpile nearby. Approach with caution, as a large Cellar Bugworm will pop out of the center of the pit. Avoid it for now as best you can. It will likely be too strong for your team at the moment.
Outside the room are a few Singing Brogs. Donít let their size fool you, theyíre manageable. Thereís a path that wraps around to the southeast, but itís essentially just a shortcut to an earlier part of the cave. There is a UM waiting for you that should be easy to defeat with your team, so keep an eye out for the Mining Patrichev next to the ramp.
You should be close to the goal at this point. Head towards the flag on your map and youíll enter the Mag Mell Ruins.
Mag Mell Ruins
After the cutscene, the game suggests that you travel to town to reequip your party, but itís merely a suggestion. My suggestion is to carry on! Explore this floor of the ruins for a moment and youíll see an inaccessible room along the northern wall. Thatís all thereís to see for now. Head up the ramp and take a right when you reach the top. If you take a left, youíll notice a flashing red beacon, but thereís nothing you can do to it or with it at this point.
Head through the green doors and youíll encounter a group of Mell Lizards. If you stick around to fight them, a Unique Monster (Wallslide Gwynry) will appear from the south to join the fray. He presents a bit of a challenge, but it's certainly possible to defeat him. If you attempt to beat him and die, youíll be sent back to the ruins, so itís not terribly risky to give it a shot.
There is an apparent mistake in Special Lever 2 for Regbuilding Colony 6.† It says defeat Earth Nebula at Sap Cave.† I was never able to find a Sap Cave, but I was able to defeat Caris Nebula at the brog lake just before you get to Nopon Arch.†