Due to Karl influencing his direct descendants via the Founding Titan power into continuing the deception, the Eldians on Paradis island believe that they are the only remaining humans and assumed the Titans were responsible. Unlike those who possess the Titan power, the Pure Titans are barely conscious as they instinctively attack and eat any human on sight. Their skin is tough and difficult to penetrate, and they regenerate quickly from all injuries, except for a spot at the nape of their neck, making hitting that spot the only way to kill them. The Paradis Eldians developed their own military branches to combat the Titans, the foremost being Survey Corps (調査兵団, Chōsa Heidan) who willingly attempt to reclaim territory taken by the Titans and are heavily derided in society because of their apparently senseless high casualty rate and little sense of progress. The second and largest branch is the Garrison Regiment (駐屯兵団, Chūton Heidan), who guard the walls and the civilian populace. The third branch is the Military Police Brigade (憲兵団, Kenpeidan), who guard the royal family and live relatively relaxed lives in the innermost wall, although this eventually results in fraud, corruption, and political subterfuge. The soldiers use a grappling, tethering system called Vertical Maneuvering Equipment (立体機動装置, Rittai Kidō Sōchi) that allow them to jump onto (and swing from) walls, trees, or nearby buildings to attack Titans with dual swords, using gas canisters to propel themselves. However, despite it being the soldiers' primary line of both offense and defense against the Titans, it is useless in open and flat terrain like fields.