Shadow Exploration is a recurring event every fourth week of each MIGO stage. The event is active for 7 days, however you can gain points only Monday to Friday (5 days) and on Saturday and Sunday (2 days) you can only access the shop and redeem items using purple samples.

The mechanics are similar to the Kamute event we had during anniversary 2020 and the plague zones, there are several levels (rooms), only when each floor boss is cleared a new one appears. You can move between the levels using the elevator or the map in the upper part of the screen.

To reach the next stage you need to clean the poisonous fog around the boss room where the elevator is located.
Mini bosses can be cleared too, but their only purpose is to give high purity antibody (green sample) for alliance leaderboard and to refresh the shadow exploration store.


Oxygen is the stamina of shadow exploration. You start with 240 oxygen that replenishes over time. The first time the event opens you keep accumulating oxygen from reset until your first login, however the following days you can’t overstock your oxygen amount. If you run out of oxygen you can purchase it for 1000 bios (40 oxygen) or with cash.

Cash oxygen can be bought once daily during the duration of the event. Oxygen bought with bios however refresh daily at reset.

When attacking a floor boss or mini boss the battle is divided in two stages : first is explore trail type of stage and it costs 16 oxygen the second one is a regular squad stage and it costs 12 oxygen. These costs can be reduced through research. Tile hitting the poisonous fog is always a squad stage and costs 12 oxygen.

This three type of samples can be obtained in shadow exploration:

  • purple sample (cell sample): higher your damage, higher amount of purple sample you get. This is the point score item, but also the currency of the shop. You can spend the purple sample in your “wallet” this will not decrease the amount of sample indicated in the leaderboard. Unspent samples will be carried over the to the next stage.
  • blue sample (research): you get a fixed amount of research for each battle, once you reach 100/120/150 research, depending on your MIGO stage, you can pick a benefit. You can increase the research by picking specific benefit cards.
  • green sample (high purity antibody): only awarded when you rank top10 for boss/mini boss damage, this “currency” is used to refresh the shadow exploration shop and counts in alliance leaderboard. Unspent samples will be carried over the to the next stage.


Each tile/boss/mini boss have its own boost that can be negated by levelling up the skills in the benefits tree.

The negation effect can be located under “infected feature” and will act as boost for your exploration/squad, when active (a red cross is displayed on the icon when the requirement are met).
Focusing on tiles/boss where you have the higher suppression will give you more purple sample (points). 


These are the shop items available. You can get up to 20% discount through research.


You gain research points passively: the bar replenishes automatically over time, or actively by hitting bosses or fog tiles. When the bar is full you can pick  one out of 3 random benefit cards.
The starting amount of the research sample is 20 and can be increased with specific skill tree/benefit cards.

IMPORTANT: during MIGO stage 1 (month 1/week 4) the bar is capped at 100, however stage 2 (month 2/week 8) the cap to get a new benefit is 120 and on stage 3 (month 3/week 12) the cap reaches 150.

Each benefit card has a certain amount of points blue (20 points), purple (25 points), yellow (30 points) to raise a specific skill tree.

This is the full skill tree for shadow exploration

LV.1 Infantry Attack +50%
LV.2 Rider Attack +50%
LV.3 Hunter Attack +50%
LV.4 Squad Attack +50%
LV.5 Damage in Exploration +20%
LV.1 Infantry defense +50%
LV.2 Rider Defense +50%
LV.3 Hunter Defense +50%
LV.4 Squad Defense +50%
LV.5 Oxygen Tanks for exploration -1
LV.1 Infantry has 20% chance to evade Damage
LV.2 Riders recover 20% Health when being attacked
LV.3 Hunters have 50% chance to double Damage
LV.4 Price of items in the Store -10%
LV.5 Research Points after each battle +10%
LV.1 Squad Attack and Defense +12%
LV.2 Squad Attack and Defense +12%
LV.3 Squad Attack and Defense +12%
LV.4 Squad Attack and Defense +20%
LV.5 Squad Attack and Defense in Exploration +20%
LV.1 Price of items in the Store -10%
LV.2 Oxygen Tanks for Explorer Trail -1
LV.3 Research Points after each battle +20%
LV.4 Cell Samples after each battle +10%
LV.5 Oxygen Tanks for March -1

There is a known bug on the develop tree: LV.4 and LV.5 bonuses are swapped. At level 4 you will use -1 less oxygen for your squad hit, even if to send out your march you will need the regular amount. Only at level 5 you will unlock the extra cell samples.

The skill gained during shadow exploration event reset back to zero for each stage.

Each card stacks up, a 1/2/3% increase attack (base on the card colour) explorer trail. You can check your total bonus by clicking on the benefit icon in the lower right corner of the screen, then read the last line of the text bubble from the professor.


Both for F2P and P2W is beneficial to focus early on getting more research > faster access to benefits > easier to level up skills > more purple samples in the long run. This means focusing on skill and develop, followed by balance/storm and last defend.

You can only stack up to 15 cards of the same type. The best card to pick related to increasing sample gain are the following ones (from best to less optimal): Advanced Research, Supplies and Sampling. If one of this three cards is available, it’s a must-to-pick.

When forced to pick between other cards try to pick a bonus that might be useful like picking attack boost to riders/hunters and not a health one. Additionally avoid to pick the card basic training from balance with a common hero boost, because it refers to the blue heroes (Rusty/Ghost) while rare heroes are the purple ones.


During squad stage there is no “best hero formula” that can guarantee a determined amount of purple sample during this event.

Yes, purple sample is determined by how many waves of infected you defeat, or by the amount of damage that you deal. This is a sum of the type of heroes you have available to use and their rank, but also the level of their hero gear therefore high spender definitely have an advantage, however the amount of sample gained is heavily influenced by the amount of benefit cards you can put together.

I.e. Let’s say you have the rider hero Julie and Tweak both at the same rank, on a theoretical level using Tweak should give you more purple samples, because even if the rank is the same the stats on Tweak should be higher, however if you picked as card benefit tactics optimization (each female hero increases Attack of the Squad by X%), you might will find beneficial to use Julie with other female heroes (like Brooke and Roxy) because the stacking amount on the card will compensate the basic stat of the hero.

If you just started your account or you are F2P, you have oxygen to spend but no exploration trail is available and the only female in your squad is Maddie, it makes little to no sense to pick tactics optimization, however it could be beneficial to pick the pet (each Hero with a pet increases the defense of the squad by +X%) one and use Maddie/Daryl. Additionally if you’re in a new state you might also have access to Ray&Rolex, so it’s definitely worth a test.


In early days of shadow exploration, especially for f2p player or low spender with no access to latest generation/high rank legendary hero/hero gear, it is better to focus the effort in the exploration trail stage of the boss.

Heroes that work well in exploration trail stage are: Mike/Maddie and as brawler Ash/E&E.

Yes, both the brawlers are legendary heroes but you can get them through Ray’s and it’s quite affordable for a f2p/low spender to rank them up at least to 2 star (Lieutenant Colonel). It’s also possible to replace Maddie with Miho, however until they release the Miho version of Travis event she’s locked behind a pay wall and not easy to obtain.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Website Powered by WordPress.com.

Up ↑

%d bloggers like this: