A fairly simple servitor, but with an unusual functionality. You may not think so when reading the description, so let me explain: Normally hand to hand combat is done using offensive means and defensive means. A weapon and a shield. You attack with the weapon and block with the shield. If you have no shield, you learn parrying techniques, such as fencing or other martial arts where the weapon is also a "shield." When warfare evolves, there comes a time when the weapons are too powerful and cannot be parried by hand, such as guns with bullets, cannons and grenades. The only way to defend then is to use external fortifications and evasive methods to completely avoid the attack.
At this time, barrages of bullets from a machine gun or continuous artillery fire can function as a shield. It stops the enemy from advancing, they cannot break through because they are annihilated if they try. This is to again create a shield from a weapon, but instead of parrying an attack, this relies on the weapon being so powerful that one cannot defend against it.
The frontline warfare relies entirely on this.
Previous ages had field battles with maneuvering, even when guns existed because barrel loaders were still ineffective and could not create the "barrage shield" effect. There were some cases when this still would happen, such as during city sieges. The Romans faced an enemy using a kind of large crossbow which could accurately pierce the neck of commanders from 200 meters away, forcing them to move out of range to uphold the siege. This is still not an actual "line" combat situation, because it's an encirclement with unbalanced terms for the two sides.
Modern magic (psychic/psi) combat has not reached the frontline stage, because as of today all attacks can still be parried or blocked using shields. Almost all attacks can be stopped this way, so it equals hand to hand combat with sword/spear/arrow and shield.
There has yet to come a situation where the enemy must evade to not be annihilated, at least the understanding that this is needed hasn't formed. This current situation for that reason is still operating as if it's a police force or a "combat squad", a small or larger unit given a specific mission with a target, then using technical means to achieve the goal, which usually means to kill/capture/subdue an enemy or retrieve information.
This unit and the theory behind this will instantly collapse when facing weapons which cannot be parried. They rely on being able to stand their ground without hiding.
