In a general sense, stealth is the ability to move or remain undetected. It is the ability to go unseen and unheard. In war, it is a crucial concept because it allows you to get into a favorable position to launch your attack.
Charging into a well-fortified compound is suicide and all the locations you enter already have enemies in set positions or on patrol routes. Not every situation will allow for a stealthy approach, but your goal is to put the enemy at a disadvantage by moving unseen and unheard whenever possible.
Stealth has many applications that depend on the condition of the battlefield and placement of enemies.
In most cases, this means moving into a well-fortified position with excellent cover or great angles. But stealth also can be used to launch a sneak attack with the element of surprise to gain a tactical advantage.
Visibility
Visibility is displayed graphically in the merc overview. The shorter the bar, the less visible you are. Your mercs will remain unseen if they are beyond the field of view of an enemy or if there is a large enough object to hide behind.
The tactical use of concealment is to hide in plain sight through camouflage. There are four different types of camo: woods, urban, desert, and night. In an obvious sense, wearing the right kind of camo will make you less visible in that terrain.
The tricky part is to outfit your mercs with camo that can be used in the most common natural setting that you fight in. Your merc’s head, torso, and legs can utilize different types of camo.
They can be mixed to provide a broad spectrum of coverage or simply focus on the terrain that seems to give you the most benefit.
It doesn’t make a lot of sense to carry extra sets of armor for each merc, but you can outfit your squad with some different types of camo and switch similar types to one merc to give them a collection of camo to sneak in for an intimate stealthy attack.
Noise Level
The amount of noise you make as you move is also displayed graphically on the merc overview next to their profile. Any type of movement will generate some sound, and only standing completely still will make you silent.
In general, the lower the stance you are in, the slower your movement and thus the less noise you create.
Therefore, you can move around at run or ready stance when you are far from the enemies, but the closer you get the lower you should go. Moving in the prone position may be slow going but it is your best chance to get into position and take the enemy by surprise.
Still, even creeping on the ground like a snake will make some noise and it can alert guards. If any foes make a comment about “hearing something,” stop dead in your tracks. Wait for their suspicion to pass and hopefully they will go back to ignoring you.
Skills and Traits
There are a few special abilities that make some mercs as stealthy as a ninja. The most obvious is the stealth skill, which can further suppress the sound the merc makes. With enough points in this skill, the merc can creep in very close to an enemy if they can remain unseen.
On the opposite side of the equation is the chameleon trait that allows the merc to blend into nearly any environment. This is an added bonus to any camo that might already help conceal them.
An extremely effective merc will have both of these abilities. When both are used with a low stance and compatible terrain, these mercs are practically ghosts on the battlefield.
Stealth Kills/Silencer
The objective of using stealth is to get into a great spot to attack your enemies while not alerting them to your presence. A stealthy merc will blow their concealment if they open fire with a loud weapon.
The silencer is a perfect companion for any merc who has the task of quietly eliminating someone. This may not work on all weapons, but when you are standing at point-blank range you don't need much firepower.
Melee masters can attempt a stealth kill by sneaking up on an enemy and incapacitating them before they have a chance to fight back. Stealthy kills like these are slow to execute and are effective against single enemies.
The goal with these attacks isn’t to wipe out an entire base but to remove a guard who could alert others and clear a path for the rest of your squad.