Aldebaran

Aldebaran is a Stage IV Gastrea that appears during the Third Kanto War arc. It is named after the brightest star in the Taurus constellation, due to the fact that it was known as the "right-hand man" of the Zodiac Gastrea Taurus, during the early years of the Great Gastrea War.

History
Taurus and Aldebaran were infamous for their organized attacks in many parts of the Asian continent, with Taurus being near-invincible and Aldebaran being able to secrete swarm pheromones to control the other Gastrea. After Taurus' defeat by the IP Rank 1 Initiator, Aldebaran reappeared during the Third Kanto War arc.

Synopsis
Because Monolith 32 was made with impurities in order to embezzle money, the magnetic field produced by the Varanium was not strong enough to repel Aldebaran, who latched itself onto Monolith 32 and injected Varanium-corroding fluid into it, destroying it within a few days. It then lead an organized attack of around 2000 Gastrea against the self-defence force and civil officers of the Tokyo Area, leading to the commencement of the Third Kanto War.

Before Commander Gado died in battle, he was able to inform Rentaro Satomi about Aldebaran's near-immortality. As a result of this, the Shiba Heavy Weapons company developed the EP (ekpyrotic) bomb, which was planted inside the stomach of Aldebaran by Rentaro and set off by Shouma, finally annihilating it.

Abilities
Varanium Corrosion: Aldebaran is able to produce a Varanium-corroding fluid, which he used to destroy Monolith 32.

Pheromone Manipulation: Aldebaran is able to secret pheromones that can control the Gastrea. While individual Gastrea are weak; under Aldebaran's centralized command, they are able to overwhelm even the most guarded areas.

Regeneration: Aldebaran was able to regenerate at an unbelievable rate. Commander Gado stated that Aldebaran "will not age or die", after having split open its head and stabbed its chest with his Varanium sword. The only way that Aldebaran could be killed was if it was destroyed completely and thoroughly, until not a single piece of it remained.