Research Tree Unlocks — When Each Tree Becomes Available

By Blek (Blake - bddc.co.uk) ·

The research lab in Last Z: Survival Shooter doesn't open all 9 trees at once. Most trees are gated behind a combination of HQ level, lab level, and percentage-completion of earlier trees. This guide collects every unlock requirement in one place so you can plan an HQ-to-HQ research path without backtracking.

The trees break into three families:

  • Free / resource trees — no research badges required, paid in wood, food, zent, steel and time.
  • Badge trees — paid in research badges earned from Lab production, events and VS tasks.
  • Late-game trees — gated behind HQ 30+ and Lab 30+, dwarf everything below them in cost.

Last verified: 26 May 2026 on Server 277. If a node cost or unlock requirement changes after a game patch, let us know.

The two laboratories

Before anything else, two structural notes:

  • The Laboratory is required for every HQ upgrade from HQ 8 through HQ 35. It's the most-upgraded building on your account and the only place research happens.
  • Lab No. 2 unlocks at HQ 18. It gives you a second concurrent research slot. Buying the Research License from the Alliance Shop and keeping both labs running 24/7 is the single biggest swing in long-term research output — if you only run one lab, you're literally halving every badge spend.

Free trees (no badges)

These trees come unlocked as you build the Laboratory and have no badge cost. They're "free" only in the badge sense — every node still costs resources (wood, food, zent, steel from HQ 31+) and time.

🟢 New Home

Unlocks: Lab built (available from the start).

Why max first: boosts construction speed, the primary lever for an early HQ speedrun. Some sources list it as a soft prerequisite for HQ-related research categories — get it to 100% before chasing harder trees.

🟢 Shelter Building

Unlocks: Lab built (available from the start).

Why max first: the gate to HQ Management. Also feeds the 50% prerequisite for Peace Shield.

🟢 HQ Management

Unlocks: after Shelter Building is complete.

Contains: base-wide bonuses to HQ resource caps and upgrade speed. Gates Rapid Growth.

🟢 Rapid Growth

Unlocks: after HQ Management is complete.

Final node in the free-tree chain. After this, you switch to badges.

Early badge trees

🔵 Elite Troops

Unlocks: Lab built (available from the start, badge-paid).

Gates: Military Strategies at 100%.

Get this to 100% as soon as your badge income allows — many later trees won't open until it's maxed.

🔵 Allied Troops

Unlocks: Lab built (available from the start, badge-paid).

Runs in parallel to Elite Troops. No tree downstream requires it, so most players defer it until other priorities are met.

🔵 Hero Training

Unlocks: early — no documented prerequisite tree (typically open by HQ 13–15).

Why prioritise: hero ATK / DEF percentages compound with every other power source. Highest impact-per-badge for combat builds.

Mid-game badge trees

🟡 Military Strategies

Unlocks: 100% Elite Troops.

Faction march sizes, gathering speed, troop bonuses. Gates two of the most important downstream trees: Peace Shield (at 45%) and Siege to Seize (at 40%).

🟡 Peace Shield

Unlocks: 50% Shelter Building + 45% Military Strategies.

Key endgame node: Urgent Rescue — the survival mechanic that makes T10 wars survivable. Gates Army Building.

🟡 Siege to Seize

Unlocks: 40% Military Strategies.

Boosts rally and city-attack mechanics. Required for Field Research at 100%.

🟡 Alliance Recognition

Unlocks: early — no documented gate. Discussed in most guides as a rotation tree (work on alongside core combat trees rather than sequentially).

🟡 Fully Armed Alliance

Unlocks: early — no documented gate. Another rotation tree; pick up alongside Alliance Recognition.

Late-game / "hidden" trees

These are the trees most players don't see until well into HQ 25+. They're significantly more expensive than earlier trees and gate the strongest endgame bonuses.

🔴 Army Building

Unlocks: after 100% Peace Shield.

Boosts formation stats — the late-game grouping system for hero loadouts. Usually picked up around HQ 27–28 once Peace Shield's Urgent Rescue is in the bag.

🔴 Field Research

Unlocks: 100% New Home + 100% Elite Troops + 40% Military Strategies + 100% Siege to Seize.

What it contains: 14 nodes / 145 levels / 594,430 badges total. Includes Field Training I/II, Camo Coating I/II, Mobility Enhancement, Melee Combat, Weapon Upgrading, Target Training, Arms Assembly, Quick Assembly, Stronger Armor, Shield Upgrade, Tactical Cover and the headline Recharge Shield node at the end.

When to start: after Siege to Seize is done. Most players knock this out between HQ 26 and HQ 28.

🔴 Unit Special Training (UST / T10 path)

Unlocks: HQ 30 + Laboratory 30 (both mandatory).

What it contains: the path to Tier 10 troops. ~1.49 million badges total. Final T10 unlock node alone needs 54k badges + 8–14 days of speedups + over 1 million electricity and hundreds of thousands of other resources.

Realistic timeline: 500+ real-time days for a free-to-play account, even with strong badge income. Most accounts in your alliance will not be T10 — this is whale territory or 6-month grinder territory.

🔴 Steel Age

Unlocks: HQ 30+ era — typically opens once Laboratory reaches level 31 and earlier badge trees are maxed.

What it contains: higher-tier boosts to construction speed, research speed and healing. Designed for accounts pushing HQ 31–35 (which use the late-game Steel resource).

When to start: after UST/T10 path is complete and HQ 30 is stable. Most players treat Steel Age as a post-HQ 30 polish — the bonuses are real but you'll only feel them if you're already at the cutting edge.

Note on the Steel Factory: not to be confused — the Steel Factory is a building unlocked at HQ 14, and it boosts Guard of Order heroes. It does not produce the Steel resource. The Steel resource itself comes from late-game HQ tiers (31+).

Suggested unlock order (one sensible path)

There are many valid paths through the lab. Here's a defensible default for a non-whale account pushing HQ 30:

  1. New Home → 100%
  2. Shelter Building → 100% (also gates HQ Management and Peace Shield)
  3. HQ Management → 100%
  4. Rapid Growth → 100%
  5. Elite Troops → 100% (unlocks Military Strategies)
  6. Hero Training → 100% in parallel — best ATK/DEF per badge
  7. Military Strategies → push to 45% (unlocks Peace Shield), then 100%
  8. Peace Shield → 100% (Urgent Rescue is the goal; also gates Army Building)
  9. Siege to Seize → 100% (gates Field Research)
  10. Field Research → 100% (Recharge Shield is the goal)
  11. Army Building → 100%
  12. Alliance Recognition + Fully Armed Alliance → rotate alongside the above during slow badge weeks
  13. Unit Special Training → only after HQ 30 + Lab 30 (long campaign — 500+ days)
  14. Steel Age → HQ 31+ polish

Common questions

❓ Why can't I see [X] tree?

Either you haven't met its prerequisite tree's completion percentage, or your HQ / Lab level is too low. Check the unlock requirements above — the tree icon only appears in the lab once you meet the gate.

❓ Do I have to max each tree before moving on?

No — only for the trees that gate downstream content (the percentages above are exact). For trees that don't gate anything, you can leave them at whatever percentage matches your priorities. Hero Training and Military Strategies are the obvious "max early" candidates.

❓ Is it worth doing the free trees first?

Yes — they cost no badges. The only reason to defer them is if you genuinely don't have the resources, in which case you'd be using Rapid Growth anyway. Do them in the chain order (Shelter Building → HQ Management → Rapid Growth).

❓ When does Lab No. 2 unlock?

HQ 18. Once unlocked, buy a Research License from the Alliance Shop and keep both labs running 24/7. Without the second lab, every late-game tree takes literally twice as long.

Related tools

  • Research Trees tool — interactive tracker with all 161 nodes, badge costs and per-tree progress.
  • HQ Levels — every HQ tier's resource costs and prerequisite buildings (including which Lab level you need at each step).
  • Research overview — the original short-form guide to research as a power source.

Data compiled from multiple community sources (May 2026) and cross-checked against the in-game Lab on Server 277. Game updates can shift requirements; if something here looks off after a patch, please tell us.