Chapter 3.1 - Duty
On to the Samurai Campaign, where you once more join a faction just after they've taken a beating. That you administered.
Watch the cutscene to see your release from prison, and get your first Observable just by swinging your gaze over the downward slope of the burning city, to spot The Bridge.
Trot back to the prison doors you emerged from in the cutscene, and Observe The Jail.
Head just a little north from the jailhouse to find your first breakable cache tucked away in a corner behind a cart.
Follow the tutorial instructions to blow open the gates.
Clear the viking semi-heroes from the threshold, then exit the gate and turn left for another clutch of pots.
Your current objective is to exterminate the marked Vikings. To avoid missing a collectible when the scene shifts, make sure you go to the burning bridge at some point before they're all dead, and Observe the Waterfall to the right/southwest of the bridge. You can get a vantage on in from the nearby balcony or rooftop.
With that done, you can slaughter to your heart's content, either blade to blade or by shooting fire arrows from the rooftops. But eventually you'll want to make your way uphill to the north side of town, to find this very important intersection.
In the middle of the intersection, is the Observable Obelisk.
Up the hill west, near-and-to-the-right-of the giant barricaded gate, is a fierce sculpture Observable as Cross-Legged Statue.
East is a cache of Breakables guarded by several Vikings. Make note of the the location because, if you detonate the nearby lamp, the jars will break and the salvage become harder to spot.
Once you've cleared the guards and gotten the goods, look up to the tall tower here for the Observable The Imperial Palace.
That's everything in this section of the mission, so kill any objective-marked Vikings you haven't yet, and head to the bridge.
Once you're past the bridge, turn left for another set of Breakables on a wooden platform, up a few steps.
In the center of this plaza is giant tree observable as Mushroom Tree.
Talk to Momji to trigger to next part of the mission- defending the mushrooms from the Vikings. Which is not something I expected to be doing. Grab the poison pick-up from near the tree, and place them about the grounds.
You can't trigger your own traps, so don't be shy about putting a few close to the tree. Defend the area when troops come pouring in. Poisoned enemies are stunned and disoriented, so hack them down first, then mop up stragglers who escaped untainted.
The game will alert you when the mushrooms themselves are being attacked, so rush to defend them when that happens. You'll have to go through several waves of Vikings before finally capturing this zone, and clearing the objective. Next up, it's time to move the front again.
On either side of the battleground is a collectible. To the left, or easthand side, on a balcony filled with archers, is the last Breakable cache.
On the righthand or western side of the scrimmage is a giant Statue that serves as the mission's last Observable.
Once you have those in your pocket, go ahead and clear the field.
When the enemy is sufficiently decimated, a cutscene will roll, and you'll find yourself facing a cavalry charge. You can't dodge or parry, so just block each blow. Remember that, as orochi, you don't have a default block.
Once that's done with, the mission is over, and Apollyon puts her theories into practice once more.