This is a guide for Chapter 6 of Xenoblade Chronicles 3, covering Mio’s Side Story in the Aetia Region, Upper.
How to begin Mio’s Side Story
Upon entering the upper part of the Aetia Region, walk forward a bit to be introduced to Captocorn Peak. At this point, some cutscenes will play and you’ll automatically begin Mio’s Side Story at the end. If this is your first Side Story, they’re essentially Ascension Quests for the 6 main characters (you can do Lanz, Eunie and Taion’s before this).
How to reach Colony Omega
To begin with, travel south for a while, until you approach a t-junction. After some more cutscenes, make your way east/south-east along Tsang Road. At the moment, you can’t go along the south-west branch. Eventually, you’ll stumble upon Tsang Camp, which is a good spot to take a break. When you want to advance the story, choose to “Rest”.
After regaining control, continue south, then east and you’ll reach Colony Omega before long. Around here, near Colony Omega Camp, you’ll encounter your first roadblock: a squadron of eight Keves/Agnus troops. Although there are many of them, they shouldn’t be too challenging–and if you can’t defeat them, you should be worried about what’s coming next.
Next, go around the corner to reach the front of the Colony Omega Ferronis. Around here, there’s another squadron of eight Keves/Agnus troops. Show them who’s boss, but don’t lower your guard, because the real battles will begin soon afterwards…