Combat System

## Overview

If you remember the Tutorial, you probably have a general idea of the game's Combat System: Each round you can choose between 4 Actions for each unit to defeat all enemies, you know, basic Turn-Based game features. You can make your way around most Early-Game stages just fine with only this knowledge and there's not much to talk about either.

This page instead is meant to cover some lesser-known facts that are useful and/or necessary to clear more difficult stages.

## Multiple Squads

You may notice that in some stages, you can bring more than one Squad to clear them.

Although this feature is very simple, there are still few points to take note of when using Multiple Squads.:

* Squads can only be changed between waves or when the previous Squad is wiped out, in which case the battle starts over at round one, with the enemies keeping their current HP and all buffs/debuffs from the last battle removed. This makes it's impossible to use multiple squads on auto.
* Units from all the Squads are counted towards 4★ Missions. For Example, one of the Missions is "★Clear without sending AGS Units" and you bring the 1st Squad with no AGS and the 2nd with some AGS. The Mission will always fail even if you never actually use the 2nd Squad in the fight.

Friend Squad
Friend Squad behaves similar to normal secondary Squads and obey mostly the same rules as them, with a few exceptions:

* Friend Squad can only be added to their designed slot (Blue Border with "Friendly" instead of "Squad"). Some Stages allows multiple Squads, but no Friend Squad.
* Friend Squad can only be switched out between waves. When all of your Squad are defeated, the stage fails even if there's still Friend Squad left.
* You can only bring one Friend Squad.
* Units in the Friend Squad ALWAYS start with 2/3 of their HP, even if they're Broken (<25% HP).
* Each Friend has a 24h cooldown to use their Squad. However, this can be skipped by deleting and adding said friend again.

Friend Squads are very useful to get First Clear Rewards of maps that you can't normally beat, especially if you have friends willing to do the Cooldown Skip for you. However, since it must be switched out between waves, it cannot be used in one-wave stages and you need to clear the first wave yourself.

## Time Order

Before the 2.0 Update, Time Order was part of an extremely complex system that we called **Effect Activation Order**. After the 2.0 Update, this was greatly simplified, with only Time Order left largely unchanged.

A simple summary of the Time Order can be seen on the right side.

At the End of Round, all effects with a duration have their duration reduced by 1. At the End of Wave, all effects, except a few such as Recon and some Form Change, are removed.

There are a few key points from this chart:

* What SPD and AP are and how they affect turn order. This is quite convoluted and this has its own page. See Speed and AP.
* When a buff/debuff says it lasts for x rounds, that already counts the round it's applied. Since buff/debuff have their duration reduced by 1 at the End of Round, they have less duration when checked next round, which often leads to confusion.
* When a "Start of Wave" effect is removed by buff removals, it will be gone for the rest of the wave. On the other hand "Start of Round" effects will simply be re-applied next round.
* If there's no enemy left, it jumps right to End of Wave without going to End of Round. This is extremely important because of the following reasons:
	+ Skipping End of Round DoT damage. For Example, when using Broken Emily, instead of letting her clear 1 row of enemies per round (thus taking DoT damage 2 times), you can clear one row first, wait and clear both the other 2 rows in 1 round when Emily has 20AP (thus only need to take DoT damage once). This is a useful trick to have since using Broken Emily (which is one of, if not the most overpowered unit in terms of manual play) requires planning around her limited HP pool.
	+ The last round never actually "finish", and thus doesn't count towards the round count in 4★ Missions. Ever wonder why 3-6 in Main Story has "★Clear after defeating 8 enemies within 1 round" but there is no wave with 8 enemies? This is the reason.

## In-Combat Stat

One of the useful features most people never actually cared about. You can hold the chibi sprite of characters (both allies and enemies), or their icons in the Turn Order Bar to open a popup that shows details about their current stats and skills similar to the one in the picture.

This feature can be used to provide additional information that you can use to build your team perfectly for a stage:

* It shows the current stat in combat, including all the stat buffs/debuffs currently applied to units. This can be used to check for important thresholds that units have to pass: CRIT, EVA, ACC or Elemental Resist.
* It shows the AP of all units up to 5 digits after comma, for both allies and enemies, which greatly helps with controlling the Turn Order and plan your move around.
* It gives the duration of buffs and debuffs. This one is really useful for tackling difficult content such as Sanctum of Alteration, Infinite War, Challenge or C-Stages in Events.
* It gives the details about enemies' skills so you can know what they're doing and how to plan around it. Although since you're here I'd assume you can't understand Korean, so use this instead.

## Forcing Active 2

**After October 25th 2021 Update, Players can choose which Active to prioritize directly (see Unit Details). This section is kept here for archiving purposes.**

First of all, I must tell you that not all units can be forced to use their Active 2, only a few can use their Active 2 in auto mode.

In order to use this, you should first understand how units choose their skills in the Action Selection phase:

* They will always try to use their Active 1 first.
* If there are no valid targets for Active 1, they will try to use Active 2.
* If there are no valid targets for Active 2, they will idle.

That is simple enough. Now from this, you can only force a unit to use their Active 2 if 2 requirements are met:

* They can't choose a valid target for their Active 1.
* Their Active 2 is either a buff for allies, or has a higher Range than Active 1.

The second requirement is fixed for each unit so there's nothing we can do about it. So let's assume we have a unit that fulfilled the second requirement, how can we make sure that there are no targets for their Active 1?

The answer is to place them in the Backline while their Active 1 has 2 or less range (or Midline with 1 or less and Frontline with 0 Range, but they're rarer). Considering that most units have at least 3 Range for their Active 1, you need to use either Assault OS / Enhanced Assault OS or A-Rank Gremlin, or a combination of both, to reduce their Range (This is why Assault OS is one of the equipment that you should keep at least a copy anytime, even non-SS).

## Targeting Priority

This section cover how units (both allies and enemies) choose the target for their skills.

**NOTE 1:** When in manual mode, your units will ALWAYS follow your command, regardless of priority. The way allies priority their target is only applied in auto mode, or when there are no valid targets left in the area chosen by you.

**NOTE 2:** When multiple valid targets fulfilling the same level of priority, the target is chosen randomly among them.

**NOTE 3:** The priorities only apply to normal attacks chosen in the Action Selection phase, not **Follow Up Attack** and **Cooperative Attack**.

From the lowest to highest priorities, we have:

Normal Priority
Before the 2.0 update, allies will choose their target randomly among valid targets. After the 2.0 update allies will choose their target so that they hit the most enemies possible with their AoE attack.

**NOTE 4:** This DO NOT mean they will use Active 2 if their Active 2 can hit more enemies than Active 1. Ally units always use Active 1 if possible, see above for how to force units to use Active 2.

**NOTE 5:** The target is chosen in the Action Selection phase, before anything in the Action Execution phase takes place. What this means is that the target is already locked when the Action Execution phase starts and cannot be changed unless there are no valid targets left. For example, if unit A chooses an Area of 3 enemies as targets and unit B moves first and kills 2 of them, leaving only 1 left; unit A will still target the chosen Area with 1 target even though there are other ways to hit more enemies.

For enemies, unfortunately, the only way to pinpoint their target priority is with experience. However, there are still some common priorities that Players should know about:

* Target the frontmost unit (which most Ironworm follows)
* Target the backmost unit (Commonly found in Sniper Ironworm)
* Target units of a specific type (Light/Flying/Heavy) (usually when the Ironworm has Anti-Type bonus)
* Target unit with the highest/lowest stats (normally HP/EVA/DEF)
* Target the last unit that attacked it
* Target randomly

**NOTE 6:** Enemies can have different targeting priority for each of their Active.

Marked
The second Priority is the  Marked status. Both allies and enemies will prioritize targeting Marked units if possible, ignoring the normal Priority.

This is important to take note of as having an enemy marked may be useful to focus down an enemy, or be harmful and disturb the AoE that your units normally follow (I'm talking about you, Khan), depending on how use it.

It can also be used to your advantage as using self-Mark units such as Tyrant, S-Rank Lindwurm and A-Rank Miss Safety is a good way to force enemies not to target your weaker allies.

Provoked
The third and highest Priority is the  Provoked status. Any units inflicted with Provoked will always choose the debuff giver if possible, ignoring the previous 2 priorities.

This is the tool some Defenders use to protect their allies, but since all skills with Provoked are single-target (at the time of this writing), it is not made use of often.

**NOTE 7:** Similar to **NOTE 5**, Provoked and Marked DO NOT affect targets already chosen in the Action Selection phase. They only take effect starting the next round after they're applied.

**NOTE 8:** There are exceptions to these rules, such as the enemies in Challenge 3 **Berserking Failure** where they prioritize summoned units even though they're summoned after the Action Selection phase.

## Protecting Priority

Covering how multiple Protect buffs interact with each other. This is mostly a copy of the corresponding parts of Effect List.

Target Protect
Receiver is protected by Target Protect giver.

Target Protect can be activated even if the giver and the receiver are both in the AoE of the incoming attack.

If the Target Protect giver is inside the range of Row / Column Protect, the giver will not be subject to Row / Column Protect.

Depending on the AoE of the incoming attack, multiple Protectors can protect their respective targets.

Target Protect won't activate if the receiver is already in the range of a Row / Column Protect.

Target Protect won't activate if the receiver has Row / Column Protect and need to protect other targets with Row / Column Protect.

If 2 or more 'Target Protect' receivers from the same giver are attacked, the one with the lower HP will be protected (last to receive Target Protect if tie).

Column Protect
Unit protects allies in the same vertical line.

If there are multiple units with 'Column Protect' in the same column, the one with highest HP will protect (last to receive Column Protect if tie).

Depending on the AoE of the incoming attack, multiple Protectors can protect their respective targets.

Column Protect won't activate if the protected target is already in the range of Row Protect.

Column Protect won't activate if the protected target has Row Protect and need to protect other targets with Row Protect.

Row Protect
Unit protects allies behind Unit in the same horizontal line.

If there are multiple units with Row Protect in the same row, the one with highest HP will protect (last to receive Row Protect if tie).

Depending on the AoE of the incoming attack, multiple Protectors can protect their respective targets.

**NOTE 1:** The units with **Target Protect** buff are the ones being Protected, while for **Row / Column Protect**, they're the one protecting. This distinction is important for when enemies have Buff Removal, in which case **Row / Column Protect** can be removed and the Protector can't use them again until re-applied. For **Target Protect**, since the buff stay on the Protected, not the Protectors, when buff removal is used against the Protectors, they can still protect their targets.

**NOTE 2:** **Target Protect** can only protect one target at a time, while **Row / Column Protect** can protect all of the subjective targets.

## Ground Targeting vs Unit Targeting

When browsing the Wiki you might have noticed the "(ground targeting)" and "(unit targeting)" added in Active skill description. This is added to specify the targeting mode of the Active, which have their own pros and cons and can affect how units use their skills drastically.

Unit Targeting
* All single-target Actives are Unit Targeting.
* The "center" of the AoE (indicated by the blue zone both in-game and in Wiki) can only be targeted on a unit and not empty ground, which limits the Areas that can be chosen to maximize numbers of enemies hit.
* If the target of the skill moves elsewhere, the "center" moves with it (Unless out of range, then normal target rule apply to find a new target).
* **Follow Up Attack** and **Cooperative Attack** will always choose their "center" the same as the targeted "center".

Ground Targeting
* The "center" of the AoE can be used on empty ground.
* If units moves out of the targeted area, the Active will still choose that area (Unless there is nothing left, then normal target rule apply to find a new target).
* **Follow Up Attack** and **Cooperative Attack** will randomly choose one surviving enemies as their "center".

## Between Waves

Often forgotten about since it is skipped entirely in auto mode. There are several actions that can be taken between waves, which can be helpful for players wishing to get First Clear Reward in manual mode:

* Changing Squads (as mentioned in **Multiple Squad** section).
* Move units around to prepare for next wave.
* Recover the HP of units using Quick-Fix Nanomachines and Resources, similar to the Recovery Room (Only for surviving units).
* Check unit's stat (Do note that most buffs are not applied now).
* If Recon Effect is active, you can also check for enemies of the next wave.

## Broken State

When a unit finish a battle with less than 25% HP, they enter the state often called **Broken** or **Damaged**. Broken units will not recover HP to full like normal and instead stay as what it is after leaving the stage.

Contrary to what most might think, the Broken state is extremely useful since there exists units with passives that need them to stay at low HP, such as May, Veronica or Emily. These Passives are intended to be used with risks and thus are stronger than normal Passive should.

However, with careful planning, Players can make use of the Broken state to activate these powerful passive while having no risk of the units actually dying.

Besides that, units with Enmity buff ( Lower self's HP is, increases DMG dealt up to XX%) can make use of the low HP to maximize their damage.

In addition, certain units need their allies to stay at low HP to trigger their passives, such as Eternity or Azazel. As aforementioned in Protecting Priority and Targeting Priority, you can use the low HP to manipulate the targeting of enemies while make your Defender unit to prioritise protecting certain unit.

The **Broken** state can be removed with Quick-Fix Nanomachines (In Recovery Room and between waves) and will be removed if the unit leave battle with triggering  Battle Continuation and more than 25% HP afterward (only applies to the stages that would sync units' status, like Main Story, Event or Sub Story stages).

This gave rise to a trick commonly referred to as **HP Shift**, where the unit is equipped with HP equipment (and sometimes even go full HP stat) before getting broken, then changed back to their normal equipment. This allows units to have low HP when entering battle, but not as low as 25%.

This trick is usually used for Emily and Faucre

* Emily: she will ALWAYS take damage at the End of Round if she uses Actives in Broken State. The extra HP can help a lot with her limited HP pool (similar to the trick in **Time Order** section) since it let her deal damage a few more time before dying.
* Faucre: Her Passive 2 grants two different sets of buffs depending on whether her HP is higher or lower than 50%. However, if she has exactly 50% HP, it will fulfill both conditions, and her Passive 2 will grant both sets of buffs to her.