My Savior...

My Savior...‏‎ is an event that took place ten years prior to the current storyline.

Prologue
During the Great Gastrea War, Rentaro Satomi loses both his parents, leaving him to fend for himself. However, during their funeral, Kikunojō Tendo willingly invites him into the Tendo Household; the latter initially dismiss the offer and rapidly runs out the funeral telling himself that his parents are still alive. Ultimately however, Rentaro returns to the man and is warmly welcomed as his foster son, meeting the elderly man's granddaughter: Kisara Tendo.

The Attack
When Rentaro is introduced to Kisara, the two becoming great friends rather rapidly. At times, Kisara's male siblings would pick on Rentaro, leading the young girl to protect him. One day whilst out on the yard, Kisara holds out her finger and questions if Rentaro understood her command, repeating once again that he is her servant and thus will do whatever she commands. Looking at the ground with an annoyed face expression, Rentaro is told by Kisara that if her brothers were to pick on him once again, she will not intervene. Just then, a large Gastrea appears behind Kisara. As Rentaro eyes the creature, Kisara turns her head to gaze at its direction.

Grabbing Kisara's hand, Rentaro pulls her behind him as the Gastrea swings its limbs to attack. Valiantly, Rentaro steps in front of Kisara and speeds his arms out to defend her from the enemy.

Aftermath
Rentaro's heroic actions are soon to conclude, however, as his heavily wounded body is quickly taken to a hospital. As the doctors around him tell one another to go faster, Rentaro opens his eye when a male doctor calls out his name; asking if he can hear him. Finally arriving to their destination, a woman looks at his body and confirms that his right arm and leg were eaten, as well as his left eye. The doctors begin writing on paper as Rentaro attempts to see his reflection on a mirror to confirm her words. His eyes land on his ridged body, causing tears to roll out from his right eye. Soon enough, the woman comes close to his face and holds out two papers, one indicating his death certificate, whilst the other being a contract that can save his life. Being asked to choose, Rentaro wishes to keep on living.

Henceforth, Kisara claims to feel secure when around Rentaro.