Tenkawa Akito's personal machine. Its jet-black body and sinister appearance evoke demons and dinosaurs, but its true identity is the Aestivalis Akito machine clad in additional armor.

Nergal Heavy Industries, the developer of the Aestivalis, was involved in its development, but Nergal denies any connection to this machine or Akito, who pilots it and carries out sabotage operations.

The machine's development was not entirely pre-planned; rather, it was damaged in numerous battles and repeatedly modified on-site, resulting in forced improvements to its performance. The parts used in the modifications were handmade using off-the-shelf products, as well as parts from test machines developed by Nergal. As a result, Black Selena's appearance has changed to the point where it is no longer recognizable as a modified Aestivalis machine, and its concept is also a completely unorthodox one that runs counter to the design philosophy of the original Aestivalis.

Additionally, the "Armored Aestivalis," developed by Nergal Heavy Industries and thought to have previously utilized parts used to modify this machine, also shared several features with the Black Selena, not just in appearance, such as being equipped with a single handgun as armament and having an external generator to deal with the inability to keep up with the gravitational wave radiation from the mothership during high-mobility operations. However, it was also met with strong opposition from some engineers as it "contradicted the design philosophy of the Aestivalis."