Yakuza: Dead Souls: Kine's underground missions and Amon
The Subterranea missions are easy to confuse with the separate Endless mode. For Amon, you need Kine's character-specific assignments, along with all 60 regular substories. The 50-floor trophy belongs to Endless Subterranea instead.
This post contains spoilers for the underground story and the Amon encounter.
PREPARE BEFORE GOING DOWN
Take batteries for the flashlight, healing items, ammunition for your stronger weapons, and armor you can fight in. A partner can distract enemies, but bring a revival item if your plan depends on keeping them active. Underground vendors may appear in the ordinary missions, but they aren't reliable enough to substitute for bringing supplies yourself.
The floor layouts vary. Use the map and look for the way down rather than trying to memorize a fixed corridor sequence. There is a prescribed final floor and encounter for each assignment. After returning to the surface, speak to Kine to turn the job in. Just reaching the floor and leaving without the follow-up conversation can leave your mission progress unfinished.
AKIYAMA
In Chapter 4, meet Kine near the quarantine entrance and investigate the Theater Avenue manhole.
Urban Mythbusting goes to floor 5 and ends with a Monkey Boy. Clear the encounter, use the exit, and return to Kine.
The Cursed Manhole sends you down again, this time to floor 15. There is another Monkey Boy encounter on the way and a full-sized Meathead at the end. Aim at the Meathead's head and keep clear of its overhead slam. Return to Kine again to finish Akiyama's assignments.
His upgraded twin handguns are useful here because you don't have to ration pistol ammunition. The completion reward is Yakuza Heroes Past & Present, the Heroic Binding design.
MAJIMA
In Chapter 4, find Kine near the eastern quarantine gate and use the Park Alley manhole, northwest of Shichifuku Parking Lot.
The Mother Lode ends on floor 10 with an Aggro. Hit it hard before it can close the gap, then inspect the person at the end and report back.
Slumbering Halls goes to floor 20. The last fight is an Arahabaki Prototype A. Keep moving away from its extended-arm attacks, use the shotgun during its vulnerable recovery windows, and counter the pounce when the Heat Snipe opportunity appears.
Finish the conversation with Kine afterward. Battlefield Adventures, the reward design, unlocks Dragon Flak Vest. That's a particularly useful reason to do Majima's underground work before a hard combat run. Some floors deliberately interfere with the light, so a dark floor doesn't always mean you forgot a battery.
RYUJI
In Chapter 4, take Kine's job and use the manhole at the northern end of the Hotel District.
After the Ravages goes to floor 15 and ends with a Diptera. Shoot during its attack recovery rather than spraying at every evasive movement. Bring the diary back to Kine.
A Truth Concealed goes to floor 25. The final enemy is Onraki. Strip the chest armor, then focus on the exposed red weak point. Watch for the throw and charge animations rather than standing still to empty the gatling gun.
Ryuji's gun can consume a lot of ammunition over 25 floors. A strong backup weapon gives you options if the final part of the descent runs longer than expected. Turn in the second half of the diary to finish the assignments and obtain Zombie Armageddon, the Survivor Training Gear design.
Helpful Links:
Subterranea assignments and Amon walkthrough: https://gamefaqs.gamespot.com/ps3/998171-yakuza-dead-souls/faqs/79387/subterranea
Amon and underground trophy requirements: https://www.playstationtrophies.org/game/yakuza-dead-souls/guide/
KIRYU
Kiryu's Implacable Fate assignment becomes available in the finale. Speak to Kine and follow the Purgatory/Florist conversation. The entrance you need is at the far eastern end of Taihei Boulevard, near the southern approach to the Champion District.
This descent reaches floor 30. I'd have the anti-materiel rifle upgraded and a good supply of its ammunition before starting. Carry an ammunition-saving sidearm for ordinary enemies, but don't force a long mutant fight with the weakest gun just to preserve every round.
The floor-30 encounter introduces Rasetsu Amon. Defeat him, complete the scene involving the sword, and return to the Florist/Kine. This first fight is not the same as finishing the later Amon challenge.
UNLOCKING THE FINAL AMON FIGHT
Finish all 60 regular substories and all of the above assignments. Complete the follow-up conversations and go to Kamiyama's truck when the message directs you there. After the invitation, return to Kiryu's Taihei Boulevard manhole and choose “Go to Amon.” You don't need to redo the full 30-floor descent for this challenge.
Bring the Dragon Rifle if you've made it, strong defensive equipment, a stack of anti-materiel ammunition, and enough healing to recover from a mistake. Roughly 100 rounds and several high-grade recovery items gives you room without pretending there is one exact mandatory loadout.
Rasetsu can grab you, fire explosive projectiles, and launch a very damaging red/dark beam attack. Watch his windup and dodge sideways out of the line. Don't backpedal directly along the beam's path. Break away quickly if grabbed, heal before returning to range, and keep firing the anti-materiel rifle when the opening is safe.
His invisibility interferes with the head-lock ability. It doesn't mean every kind of firing has stopped working. Reposition, use ordinary targeting/hip fire when necessary, and avoid standing still searching for a perfect lock while an attack is starting.
Defeating him earns Amon's Vanquisher and unlocks the Satellite Laser reward at Naomi's Palace. Collect it before moving on to your level-99 cleanup. Kiryu's short Aggro Spec-Op becomes a much more convenient experience farm with it.
Yakuza: Dead Souls: Kine's underground missions and Amon
· Games/Yakuza: Dead Souls