Mato Seihei no Slave

Mato Seihei no Slave (魔都精兵のスレイブ, translated to "Slave of the Magic Capital's Elite Troops") is a Japanese manga series written by Takahiro and illustrated by Youhei Takemura, and published in the Shonen Jump+ online platform.

Predator

 * Kuusetsu

Prey

 * Naon Yuno
 * Koko Zenibako

Scenario
After previously abducting Naon Yuno and Koko Zenibako, two humanoid shuukis, the Gods of Thunder present their unconscious bodies to Kuusetsu, a large egg-like creature that is to be the fourth God of Thunder. Kuusetsu looks them over and, apparently pleased, opens up its large mouth and devours Naon and then Koko shortly afterwards. The other Gods of Thunder observe that Kuusetsu is only God that needs food to develop and that Naon and Koko will remain as part of Kuusetsu's body for eternity. Naon and Koko remained trapped and unconscious inside Kuusetsu's body as it begins to slowly metamorphose.

Subsequently, in Chapters 54 and 60, it is revealed that Kuusetsu has taken on a female form, inheriting Naon and Koko's physical traits, as well as their personalities.