Armored Core VI: Fires of Rubicon Walkthrough — Start to Endgame

Armored Core VI: Fires of Rubicon is FromSoftware's return to their mech franchise after a decade, featuring fast-paced mech combat with deep customization. You pilot an Armored Core (AC) built from hundreds of interchangeable parts across head, core, arms, legs, boosters, FCS, generator, and four weapon slots. The stagger system from Sekiro makes an appearance — filling an enemy's stagger bar opens them to massive damage. Three separate playthroughs with branching missions are required to see all endings and unlock all parts.

This walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. Follow this path to avoid common traps that stall most players.

Quick Progression Summary

Phase 1: Getting Started — Rubicon 3 Surface

The primary battleground featuring industrial wastelands and Coral-contaminated zones. Early missions here teach basic combat against MTs and light ACs. The terrain is relatively flat with some vertical elements for aerial combat practice.

Level/Difficulty: Chapter 1-2 Key Rewards: Starting parts, OS Tuning introduction, basic weapons

What to Do in Rubicon 3 Surface

1. Learn assembly system. Your AC is built from parts across 11 categories: right arm weapon, left arm weapon, right shoulder weapon, left shoulder weapon, head, core, arms, legs, booster, FCS, and generator. Spend your first session getting comfortable with this.
2. Pick Tank Build as your starting role. It's the most forgiving option.
3. Dual Zimmerman shotguns + Songbirds grenade launchers is the most reliable boss-killing setup for your first playthrough
4. Acquire your first weapons upgrade — Songbirds Grenade Launcher or whatever's available.
5. Clear all main content before moving on.

Phase 1 Checklist

• Understand assembly system fundamentals
• Tank Build selected and functional
• Rubicon 3 Surface main content cleared
• Ready for Wall Breach

Phase 2: Early Game — Wall Breach

A massive fortified wall that serves as a pivotal midgame mission. Features both AC combat and large-scale MT encounters. The mission design teaches you to manage ammo across a long mission without resupply.

Level/Difficulty: Chapter 3 Key Rewards: Mid-tier weapons, story progression, new part shops

What to Do in Wall Breach

1. Work on stagger mechanic. Every enemy has an ACS (Attitude Control System) bar that fills when you deal impact damage. This system becomes critical from here on.
2. Farm for Songbirds Grenade Launcher if you haven't already. It's the key upgrade for this phase.
3. OS Tuning chips from Arena S-ranks are permanent buffs — prioritize boost speed and damage chips first
4. Complete all objectives before pushing to Watchpoint Delta.
5. Consider whether Lightweight Speedster might suit your playstyle better than Tank Build.

Phase 2 Checklist

• stagger mechanic integrated into gameplay
• Songbirds Grenade Launcher acquired
• Wall Breach fully cleared
• Ready for Watchpoint Delta

Phase 3: Mid Game — Watchpoint Delta

A key story location where multiple factions collide. Some of the hardest regular missions take place here with simultaneous AC and MT threats. Contains hidden paths with bonus parts if you explore off the main route.

Level/Difficulty: Chapter 4 Key Rewards: Advanced parts, faction-specific weapons, hidden components

What to Do in Watchpoint Delta

1. Master assault boost. Quick Boost (dodge) and Assault Boost (forward charge) are your primary defensive and offensive movement tools. This unlocks a new layer of gameplay.
2. Start working toward Zimmerman Shotgun. It's the best weapon and becomes accessible around now.
3. You can replay any mission from the menu with your current parts to farm credits
4. This area is the main skill check. If you can clear it, you're ready for late game.
5. Start investing in energy management for the tactical depth you'll need going forward.

Phase 3 Checklist

• assault boost mastered
• Zimmerman Shotgun acquired or in progress
• Watchpoint Delta fully cleared
• Ready for ALLMIND Research Facility

Phase 4: Late Game — ALLMIND Research Facility

An endgame facility tied to the third playthrough's branching path. Features puzzle-like encounters and the ALLMIND boss fight. Required for the third ending and unlocks the game's most powerful secret parts.

Level/Difficulty: NG++ (3rd playthrough) Key Rewards: ALLMIND ending, secret parts, final Arena unlocks

What to Do in ALLMIND Research Facility

1. Finalize your build. You should be running Lightweight Speedster or Tank Build with optimized gear.
2. Zimmerman Shotgun should be your primary. If you don't have it yet, prioritize getting it.
3. Reverse-joint legs give a massive charged jump that's excellent for aerial combat and dodging ground attacks
4. arena ranking optimization starts here. Small improvements compound into massive advantages.
5. Farm this area for the resources needed to push into Coral Convergence.

Phase 4 Checklist

• Build fully optimized
• Zimmerman Shotgun upgraded to max
• ALLMIND Research Facility fully cleared
• Ready for Coral Convergence

Phase 5: Endgame — Coral Convergence

The final mission area featuring the climactic boss battles. Different endings lead to different final bosses here. The CEL 240 and Ayre fights are among FromSoftware's most challenging encounters.

Level/Difficulty: Final chapter Key Rewards: Ending-specific rewards, final boss parts, playthrough completion

What to Do in Coral Convergence

1. Coral Convergence tests everything. Come prepared with your best build and gear.
2. The Coral Generator (NG++ unlock) has the highest energy output and enables energy weapon spam builds
3. The endgame loop: run Coral Convergence, optimize gear, push harder content.
4. Experiment with Balanced Middleweight for a fresh take once you've mastered the standard builds.
5. This is where arena ranking mastery separates good players from great ones.

Phase 5 Checklist

• Endgame content on farm
• Best-in-slot gear acquired
• Coral Convergence fully cleared
• Ready for challenge content

Common Progression Mistakes

• Building too heavy and running out of energy constantly — mobility is survival in this game
• Ignoring the stagger system and trying to raw DPS bosses through their health bar
• Not checking weight limits before sortieing — over-limit ACs move like slugs and can't boost properly
• Spreading weapon types across all four slots instead of building synergy (e.g., all stagger or all sustained DPS)
• Skipping Arena missions — OS Tuning chips are major permanent power increases you're leaving on the table

Key Tips for Smooth Progression

1. Dual Zimmerman shotguns + Songbirds grenade launchers is the most reliable boss-killing setup for your first playthrough
2. OS Tuning chips from Arena S-ranks are permanent buffs — prioritize boost speed and damage chips first
3. You can replay any mission from the menu with your current parts to farm credits
4. Reverse-joint legs give a massive charged jump that's excellent for aerial combat and dodging ground attacks
5. The Coral Generator (NG++ unlock) has the highest energy output and enables energy weapon spam builds

For detailed build optimization, see Armored Core VI: Fires of Rubicon builds. For quick wins, check tips & tricks.