Hell is Us Act 3 Walkthrough

Act 3 of Hell is Us contains a single major investigation — Into the Unknown — and pushes every system introduced in Acts 1 and 2 to their limit. Expect longer gauntlets, tighter Healing Pulse windows, multi-phase bosses, and fewer forgiving checkpoints. This walkthrough assumes you completed all three Keystones and inserted them at the Lymbic Forge at the end of Act 2.

Before entering Act 3

Finish optional content while APC routes still allow backtracking — Act 3 opens a hard point of no return once you commit through the Keystone door into Mount Obek / Golden Eye:

• Sweep remaining missables with Missables & Platinum and the platinum checklist before the finale door.
• Close remaining Timeloops for Elite Glyphs and Relics (Good Deeds & Timeloops).
• Complete outstanding Good Deeds — several award passive Relics that trivialize late swarm rooms.
• Clear pending Mysteries you care about via Mysteries Guide.
• Upgrade both weapons to current material caps and equip drone modules for crowd control.
• Stock medkits sparingly; rely on Combat & Healing Pulse mastery instead.
• Skim Bosses & Dungeons for late guardian patterns (Big Hallows / final Timeloop Guardians).

Review Puzzle Solutions only when stuck; Act 3 puzzles reuse symbol languages from Senedra, Auriga, and Plains of Mist with harder combinations.

Investigation: Into the Unknown

Opening objectives

Act 3 begins at the APC with updated Datapad entries pointing toward the unknown region beyond forged Keystones. Talk to Tania and Ernest for context — dialogue flags sometimes reveal shortcut landmarks. Travel using the same no-map rules: follow compass headings described in objectives, confirm landmarks with drone scans, and use No-Map Exploration if headings feel vague.

Mid-act gauntlets

Into the Unknown strings together combat arenas, timeloop remnants, and puzzle gates without separate investigation names. Treat each Datapad update as a chapter break:

1. Outer wastes — mixed Hollow squads and environmental hazards. Clear adds before examining anchors; timeloop shards still spawn guardians if you skip prism steps.
2. Inner sanctums — multi-layer doors requiring symbol alignment similar to Senedra inner rings and Plains plate logic. Scan every mural before touching dials.
3. Forge-adjacent depths — elite enemies that punish missed Healing Pulse timing. Swap to polearms or greatswords for hyper-armor foes if twin axes feel risky.

Boss sequences

Late Act 3 features consecutive boss phases tied to the Lymbic narrative. General pattern:

• Phase one spawns add waves — destroy structures or pillars first, matching Ecstasy boss logic from Act 2.
• Phase two restricts healing — prioritize perfect dodges and pulse only after safe openings.
• Final phase combines symbol mechanics with DPS checks — keep drone scans active to reveal weak points.

Exact names vary by spoiler policy, but the rhythm matches Keystone finales: learn spawn triggers, stabilize the arena, then commit damage during stagger windows.

Exploration and secrets

Act 3 hides vault entrances and last Good Deeds off the critical path. Listen for NPC radio chatter at the APC after each major objective — new deeds expire if you finish the finale first. Vaults of Forbidden Knowledge drop Enhanced or Elite Glyphs; see Tier List for standout picks once you collect them.

Finale sequence (spoiler-light)

When the Datapad points you to insert all four Keystones at the Lymbic Forge and descend into Mount Obek, you are in the ending corridor. For orb/statue order, Amine Prism Rho, Heirloom Necklace, and post-credits notes, open the spoiler-labeled Endings Explained page so this walkthrough stays usable mid-run.

Post-game and cleanup

After credits, reload the pre-finale save mark to explore remaining Timeloops, Mysteries, and deeds if they still exist. Patch 1.7 Guardian Detector helps Legend of the Phol Lymbic Entity cleanup. Promo rewards, when available, appear on Codes; use Tools for checklists.

Difficulty tips specific to Act 3

• Carry two weapon families with different reach — cramped rooms favor swords, open arenas favor polearms.
• Assign at least one Relic that boosts pulse healing or reduces stagger damage.
• Do not hoard Amine Prisms; any remaining loop in Act 3 is mandatory or high-value.
• If a section feels impossible, retreat to the APC, upgrade, and retry — level gaps are sharper here than in Act 2 B4.

Related guides

• Previous: Act 2 Walkthrough
• Foundation: Act 1 Walkthrough
• Finale spoilers: Endings Explained
• Completion: Missables & Platinum
• Basics: Beginner Tips