Bio Lab Progression for Advanced Troops

In Last Z: Survival Shooter, the Bio Lab is crucial for unlocking advanced seasonal troops. Specifically, it provides the necessary Virus Resistance for powerful units like Frostbanes and Snow Leopards.

Frostbane Access and Mastery Switching

To access level 60 Frostbanes early, prioritize reaching Bio Lab level 26. If you plan to switch your Combat Mastery path later, ensure your Bio Lab reaches level 28 beforehand. This ensures you maintain access to these high-level Frostbanes after the Mastery switch.

Your primary focus should be on advancing your Bio Lab to the level required by your current Mastery path before considering other combat enhancements.

Understanding Resource Needs

Bio Lab upgrades consume two main resources: Ice Blooms and Frost Cores. Ice Bloom requirements are significantly higher than Frost Core requirements for these upgrades.

Ice Bloom Production

Ice Blooms are produced by Smart Greenhouses. You can construct up to four Smart Greenhouses, with an additional fifth available through the Wartime Investment program.

Frost Core Acquisition

Frost Cores can be obtained by farming rewarded Frostbanes or by participating in scheduled alliance target rallies.

Hunter Yeti and Virus Resistance

The Hunter Yeti is a unique exception; it does not require Virus Resistance from the Bio Lab. Therefore, you do not need to delay its rallies to advance your Bio Lab. Hunter Yeti rallies should be timed based on alliance schedules, rally strength, and remaining reward attempts.

Smart Greenhouse vs. Bio Lab: When to Upgrade

Navigating your upgrade path efficiently is key. Here's a breakdown of common scenarios:

Your Current Situation	Next Action	Reasoning / Limitation
Below your Bio Lab 26 or 28 checkpoint, with both resources available	Upgrade Bio Lab	This action directly enables level 60 Frostbane access for your chosen Mastery path.
Facing a small shortfall of Ice Blooms for the next Bio Lab checkpoint	Save Greenhouse output	For minor shortfalls, let your existing Greenhouses accumulate resources. Only upgrade a Greenhouse if the increased production will offset the upgrade cost before you reach the required Bio Lab level; otherwise, it will simply delay your Bio Lab progression.
Lacking Frost Cores for your Bio Lab upgrade	Farm remaining Frostbanes	Utilize any remaining Frostbane reward attempts and join scheduled alliance rallies. A Greenhouse upgrade generates Ice Blooms and will not resolve a Frost Core deficiency.
At the Bio Lab checkpoint relevant to your Mastery path	Begin Command Post upgrades	At this point, you can redirect your investment into seasonal fighting capabilities without hindering your troop resistance progress. Compare the costs of the next Arsenal and Fort upgrades.

Prioritizing Command Post, Icy Arsenal, and Icy Fort

After reaching your Bio Lab checkpoint, begin upgrading your Command Post. If the next Command Post level requires a disproportionately high amount of Frost Cores or Ice Blooms, consider upgrading the cheaper Icy Arsenal or Icy Fort levels instead of trying to raise all three evenly.

Urgent alliance events, such as city fights or Glory War, might justify investing in combat buildings earlier. However, be aware that this can delay achieving the Bio Lab level needed for your next Frostbane tier. Remember, transitioning to a new Combat Mastery tree is a separate decision, and Bio Lab 28 is essential for retaining level 60 Frostbane access if you make that switch.

Combat Building Statistics

These buildings enhance your seasonal troops' effectiveness:

Building	Base Free-to-Play Cap	Per-Level Value	Value at Base Cap
Command Post	30	+1% Season Troop Damage	+30% Season Troop Damage
Icy Arsenal	50	+3% Season Troop Attack	+150% Season Troop Attack
Icy Fort	50	+3% Season Troop Defense	+150% Season Troop Defense

These figures represent the standard free-to-play caps. Additional levels may be available through Season Pass or Wartime Investment. Season Troop Attack and Defense provide benefits in both offensive and defensive scenarios.

Quick Tips

• Bio Lab First: Prioritize Bio Lab levels for Frostbane access based on your Mastery path.
• Bio Lab 28 for Mastery Switch: Reach Bio Lab 28 before changing Mastery paths to keep level 60 Frostbanes.
• Smart Greenhouses for Ice Blooms: Build all available Greenhouses to maximize Ice Bloom production.
• Farm Frost Cores: Get Frost Cores from rewarded Frostbanes and alliance rallies.
• Hunter Yeti Exception: Hunter Yeti doesn't need Virus Resistance; rally it based on alliance needs.
• Resource Management: Upgrade Greenhouses only if they repay their cost quickly for Bio Lab progression.
• Post-Checkpoint Combat Buildings: After Bio Lab, focus on Command Post, then Icy Arsenal/Fort, prioritizing cost-effective upgrades.