Survey Corps

The Chōsa Heidan (調査兵団), also known as the Scouting Legion, Scout Regiment, or Recon Corps, is the driving force of the plot and story as it is the branch of the Military most actively involved in direct Titan combat, Titan study, human expansion, and outside exploration. They have the best soldiers (not to be compared with the Top 10 who joins the Military Police Brigade), and are the most skilled in using the Vertical Maneuvering Equipment. But, despite having little success, they still symbolize 'the hope of mankind' with their insignia being known as 'the Wings of Freedom'. They hope that someday, their efforts will change the world and they'll be able to recover what has been taken away from humanity.

Duty
This Military division is in charge of the exploration and the eventual reclamation of human territory from Titan-infested lands through the act of setting up small bases, camps, resupply stations, and extra fortifications in available areas outside the Walls. This branch of the military has by far the highest death rate. Prior to the breach of Wall Maria by the Colossus Titan, they explored the land outside of the wall, though never getting that far due to the heavy casualties suffered from Titan attacks.

Presently, they have been laying down supplies from Wall Rose's Trost District to Wall Maria's Shiganshina District in preparation to seal the breach and reclaim Wall Maria.

A more recent unofficial duty has been Titan observation and research. Given the safer nature of exploring within wall territory (since Titans can only enter the wall at one point), a wealth of information has been revealed such as their tolerance of pain, sunlight dependence, and intelligence.

Structure
The Survey Corps is the smallest branch of the Military in terms of membership, with an overall size of around 300 soldiers. This already-limited number of volunteers is made less and less by commonplace deaths and an infamy surrounding the body count that frightens most away from joining. It is known now that the Survey Corps only has around 100 personnel due to soldiers being killed during the 57th expedition and by the Military Police Brigade.

Erwin Smith is the 13th Commander, with 2 Squad Leaders (Levi Ackerman and Hange Zoë) serving directly beneath him. A single Senior Team Leader serves beneath them, supervising 8 Team Leaders in the field. The Legion also has 6 specialized Medical Officers, 5 Veterinary Officers in charge of caring for their horses, and 5 Remuneration Officers that serve concurrently with Team Leaders. This structure leaves 270 regular soldiers, divided into 10 Teams.

Their stables also include a total of 600 specially-bred Horses. These horses are noted to be exceptionally valuable, and bred for great speed, stamina, and calm temperament.

Numbers have greatly decreased in the Survey Corps since their fight with the Beast Titan, leaving an estimated less than 10 members alive currently (not including any unseen members still within the Walls).

Qualities
Since the Survey Corps are constantly on the front lines, fighting Titans, its high fatality and low success rate discourages most people from enrolling into the legion, as seen when only 10% of the 104th Training Corps joins them. Thus, the Legion suffers a constant personnel shortage and the only soldiers who enter the Survey Corps are dedicated to the cause of humanity, usually at the cost of their own lives. In stark contrast to the Military Police, there is no laziness or incompetence in the Survey Corps, and no corruption. Whether at their headquarters or in battle, members of the Survey Corps have no one to depend on but each other. This has built a strong atmosphere of trust in the Survey Corps, and a general no-nonsense form of honesty among its personnel. Survey Corps members tell and expect to be told of the truth, no matter how good or bad it might be.

Prides of the individual soldiers are also very high, as they are aware of not only being the best of the three Military branches, but whatever progresses, victories mankind gains against Titans are gained at the cost of the scouts' lives. And as they boldly go to the realm where most humanity dares not, their pride is rightfully justified.

Trust between leaders and subordinates is absolute. As Gunther told Eren, if Erwin does not tell his men everything, there is a reason. Therefore, Eren should trust Erwin. Even Levi, with his prickly personality, tells his crew that Erwin is always a few steps ahead of others, and follows his judgement unconditionally. Oluo chastised Eren during the 57th expedition for questioning Levi, and Eren raised Petra's animosity when he raises the possibility of Levi not trusting the Special Operations Squad. Subordinates have absolute trust and admiration for Levi even as they are dying; and in return Levi would renew and confirm his determination to eradicate Titans to his men. This level of trust is necessary for a legion that has no one to rely on but each other.

While most soldiers do not survive their first expedition, each successive expedition exponentially increases their chances of survival. The Survey Corps's most hardened veterans each have numerous Titan kills to their name and, far beyond any members of the Garrison or Military Police Brigade, are the most skilled soldiers in the entire military. With its frequent expeditions outside the safety of the Walls and regular combat engagements with the Titans, however, membership in the Survey Corps is extremely dangerous. Each and every officer and enlisted man, from highest to lowest in rank, lives with the fatalistic knowledge that their next encounter with the Titans may well be their last.

Despite their small numbers, the discipline and fighting prowess of the Survey Corps is regarded as the best out of the three military branches. There is no class-based segregation between officers and enlisted men, with all ranks sharing equally in the work and dangers. The Survey Corps has a well-earned reputation for toughness and cool-headed courage in the face of extreme hardship; members will fight on even in the smallest, most isolated of groups. Survey Corps members are physically and mentally tough, highly adaptable, and can be counted on not to panic even when the Garrison and Military Police personnel around them have broken ranks.

Unfortunately, this branch is also in the most uncomfortable position, politically and financially. Despite being the best out of the three military branches in terms of the overall quality of its officers and enlisted men. The bureaucrats, rich conservatives, and many Military Police members dislike the Survey Corps and view it as a waste of money and resources. Due to the Legion's lack of definite, decisive successes and high losses of lives. Only from the 'support' of the King does the Legion still remain intact and protected from the greedy bureaucrats and hostile conservatives. Membership thus involves little glory, and Survey Corps members are thus arguably humanity's finest and most sincere soldiers- not after money, glory or promotions, but truly committed to buying humanity a better tomorrow, whatever the cost may be. Anybody can join the Survey Corps for that it does not have a certain requirement like the Military Police branch.

Strategy and Tactics
Due to the constant horrific losses suffered at the hands of Titans, the Survey Corps has been forced to fight smarter to achieve their goals. The Survey Corps use Horses as one of the main resources to explore.

Long-Range Scouting Formation
Developed by Commander Erwin Smith, the key to this formation is Titan avoidance. Because the Survey Corps cannot afford to fight every Titan out in the open, the entire Legion is spread out over a large area, maximizing visibility. Upon encountering a Titan, a red flare indicates the danger and all soldiers who see the flare fire a red flare of their own, allowing Erwin to quickly be alerted to the Titan's presence. He will then fire a green flare in the desired direction to avoid this Titan with all members firing a green flare as well to allow the information to spread quickly.

However, there are occasionally Abnormal Titans that will break it apart by ignoring scouts on the perimeter and instead, attack the middle of the formation. In this case, a black flare indicates the danger and the Titan is disposed of as quickly as possible.

The entire formation is in the rough shape of a semicircle, and is composed of the following sections:
 * Forward scouts. Presumably the most reliable soldiers, they are spread out along the front rank of the entire formation. They are the members of the Legion who come into contact with the Titans more frequently, alerting the rest of the formation to the presence of Titans using red smoke rounds.
 * Scout support teams. They are one position deeper into the formation than the forward scouts, whom they help in combat if need be. It's possible that these soldiers were responsible for holding back the Titan attack on the formation's right flank during the 57th Expedition beyond the Walls.
 * Command. The Commander of the Survey Corps is at the front of the formation, right behind the frontal scout teams. It's his job to judge the situation of the expedition, taking into account the flares fired by the rest of the formation and firing green signal flares to inform the Legion of new trajectories. The Commander is accompanied by a small number of men whose job it is to relay verbal messages to the rest of the formation.
 * Relay teams. Comprised chiefly of new recruits, it is their job to fire smoke rounds bidirectionally: both to inform Command of Titan sightings (red and black flares) and to inform the rest of the formation about a change of course (green flares). All the members of the 104th Training Corps who chose to join the Survey Corps were part of the relay teams. It is a relatively well protected area of the formation (after all, here are the most inexperienced soldiers), as it is not directly in contact with oncoming Titans and it is difficult to stray from the formation from this position. Dita Ness and Luke Siss were among the relay teams during the 57th expedition. The relay teams also ride along the spare Horses.
 * Cart guard teams. They are between the relay teams and the carts, and it is their job to protect said carts. Goggles was part of the cart guard teams in the 57th Expedition.
 * Carts. This unit is comprised by wooden carts with a special suspension system, each pulled by two horses and manned by two soldiers. Their job is to carry the supplies necessary for the expedition (food, gas, medical supplies, extra Vertical Equipments, etc.). They are very vulnerable to Titan attacks, so they are in the deepest place in the formation, riding single-file behind the Command team. The carts played a pivotal role during the 57th Expedition, as they secretly carried the artillery pieces that were going to be used to capture the Titan Shifter.
 * Standby. This group is in the most protected part of the formation: the centre-rear, behind the cart line. This position was occupied by Squad Levi during the 57th expedition. It was their job to protect Eren and to serve as bait so as to lure the Female Titan into the Titan Forest.
 * Rear guard. These are the soldiers who ride at the very back of the formation, protecting it from Titan pursuit. It is a job which conceivably entails some risk, as it is possible to fall behind the rest of the formation.

This formation has lowered the Survey Corps losses by 30%. However, it can be rendered ineffective by bad weather, especially rain, when flares will become useless. This, combined with the drop in visibility from said rain or fog will reduce the ability of the formation to remain in communication and spot Titans.

Ambush
Although not a 'true' tactic in the sense of common battle doctrine, the Survey Corps has been involved in two attempts at capture and are worthy of note given their similar procedures.

Survey Corps Ambush follows this pattern:


 * 1) Target is lured into area where Survey Corps forces have the maximum advantage. i.e. Leading target into a forest (where Vertical Equipment is most effective) or underground (where Titans cannot move).
 * 2) Target is incapacitated with the Special target capture weapon.
 * 3) Vertical Equipment soldiers surround target area and prevent escape.
 * 4) If target breaks free (e.g Female Titan breaks free twice) soldiers try to prevent escape and to incapacitate or regroup.

Trivia

 * It has been noted that even normal soldiers from the Survey Corps are, on average, stronger than those from different branches.
 * 21 graduates of the 104th Training Corps southern division joined the Survey Corps, including Eren Yeager, Mikasa Ackerman and Armin Arlert.
 * There are 49 known members of the Survey Corps, from the original manga as well as its two spin-offs.
 * In Attack on Titan: Before the Fall, the Survey Corps survival rate was even lower, due to the fact that they didn't know the weak point of a Titan or have Vertical Maneuvering Equipment.
 * It's stated that recently the Survey Corps usually goes on an expedition outside the Walls about once a month. So from the 34th expedition to the 57th expedition, it has been a total of 2 years; which would come to about one expedition outside the Walls a month.
 * There is more than one Survey Corps, but records show there have never been more than two active at any given time.

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