Pleiades

Pleiades was a Stage IV Gastrea that appeared during the Third Kanto War arc. Like Aldebaran, Pleiades was also named after a celestial body in the Taurus constellation, the Pleiades Star Cluster.

Synopsis
Shortly after Monolith 32 was destroyed, the horde of Gastrea led by Aldebaran swarmed inside the outskirts of the Tokyo Area and engaged in combat with the Civil Security Corporation. Since Pleiades was incapable of moving on its own, it served as their long-range support, firing a barrage of "light spears" that caused massive casualties for the Civil Security.

Because Pleiades was a major obstacle in their campaign against Aldebaran, Rentaro Satomi was forced to eliminate it on his own as punishment for disobeying the commander's order. On his way there, Rentaro met Kagetane Hiruko and his daughter Kohina, and the two joined Rentaro on his mission. When they arrived, they found the Gastrea sleeping, so they took this chance to kill Pleaides without resistance.

Abilities
Mercury Manipulation: Pleiades was able to shoot mercury in the form of light beams, which the Civil Officers nicknamed as the "Spear of Light". People whose limbs were cut by these "spears" experienced deafness or loss of sight, all of which were consistent with mercury poisoning.