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.
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.
- Black Bullet Anime: Episode 11
|Stage I||Original Gastrea • Sumiaki Okajima|
|Stage II||Crocodile Gastrea • Horseshoe Crab Gastrea • Shark Gastrea|
|Stage IV||Lizard Gastrea • Aldebaran • Pleiades|
|Stage V||Zodiac Gastrea|
|Great Gastrea War||Bee Gastrea • Dragon Gastrea • Giraffe Gastrea • Humanoid Gastrea • Mouse Gastrea|
|Outer Area||Firefly Gastrea|