The episode opens with Yuuki Wakura, a high school student, cleaning the classroom alongside his classmates before they arrive. His classmates compliment him on his housekeeping skills. Later that day, a gate to Mato suddenly opens and Yuuki is transported into the alternate dimension. He is instructed to hide and wait for the Demon Defense Force to arrive and rescue him.

While hiding, Yuuki is spotted by a Shuuki, a hostile creature from Mato. The creature chases him into a corner. Kyouka Uzen, the Commander of the Demon Defense Force 7th Squad, intervenes with her own Shuuki and uses her sword to slice down the attacking creature. As more Shuuki surround them, Kyouka and Yuuki are forced to run and continue being pursued.

Himari, Shishu, and Nei arrive in a vehicle and begin shooting down the Shuuki from above. They reveal that they have rescued a young boy who was also trapped in Mato. As the boy regains consciousness, he asks about his sister.

Kyouka and Yuuki spot the boy's sister running from another Shuuki. Kyouka rescues her and creates a force field around the three of them. With time running out and the Shuuki closing in, Kyouka offers Yuuki a choice: he can become her slave and gain incredible powers to fight the Shuuki. Yuuki initially hesitates, but under pressure from the dire situation, he agrees to the arrangement.

After the battle concludes and they have defeated the giant Shuuki, Kyouka asks the others for privacy. She then kisses Yuuki, explaining that this is compensation for his work as her slave. When he resists, she clarifies that the kiss is not something she can control; it is a mandatory reward she must give him. She continues to aggressively kiss him.

Following this, Kyouka explains to Yuuki that the real world is in constant danger from Shuuki attacks. She expresses her ambition to become the Supreme Commander and lead the entire Demon Defense Force. She states that this goal will not be possible without him and requests that he fight by her side to ensure her success.

Short Ending Summary

Yuuki agrees to become Kyouka's permanent slave after she uses her enslaving power to transform him into a powerful beast that defeats the shukki threatening civilians, and she rewards him with a kiss, establishing their contract as he joins the Demon Defense Force 7th Squadron.

Expanded Narrative Ending

The climactic sequence of Birth, Yuuki, Awakening unfolds as Yuuki and Kyouka find themselves in an increasingly desperate situation surrounded by shukki monsters. Kyouka and Yuuki spot the boy's sister running from one of the creatures. Kyouka moves to rescue her and creates a protective force field around the three of them, but as time runs out and the monsters close in, she realizes she needs additional power to save everyone.

In this critical moment, Kyouka turns to Yuuki and makes him an extraordinary offer. She tells him she can give him incredible powers to fight the shukki, but only if he becomes her slave through her unique ability. Yuuki hesitates at first, uncertain about what this commitment means, but under the pressure of the immediate danger and the lives at stake, he agrees to her terms.

The contract is enacted through a ritualistic gesture. Kyouka extends her finger toward Yuuki and he instinctively licks it. This action triggers a dramatic transformation. Yuuki's body undergoes a complete metamorphosis, expanding into a giant muscular beast form. With this newfound strength, he becomes an unstoppable force against the shukki. He uses his immense power to defeat the monsters while simultaneously carrying Kyouka and the young boy to safety. They manage to escape the immediate threat, but the shukki begin to fuse together, forming one enormous creature. However, this combined monster proves no match for Yuuki's brute strength, and he destroys it.

After the battle concludes and the immediate danger has passed, Kyouka asks the others to give them privacy. She then approaches Yuuki and kisses him. He initially resists the physical contact, but she explains that this is not something she can control. The kiss is compensation for his work as her slave, a price her ability compels her to pay. She continues to kiss him aggressively, making out with him despite his initial hesitation.

Following this intimate moment, Kyouka explains the larger context of their world to Yuuki. She tells him that the real world faces constant danger from shukki attacks coming through the gates to Mato. She expresses her personal ambition to become the Supreme Commander and lead the entire Demon Defense Force, and she makes clear that this goal will not be possible without him. She requests that he fight by her side permanently to ensure her success.

Yuuki accepts her proposal. He agrees to become her permanent slave and to live with her and the other members of the 7th Squadron. The episode concludes with Yuuki having transitioned from an ordinary high school boy struggling to find his place in the world into a key member of the Demon Defense Force, bound to Kyouka through her enslaving power. Kyouka has secured the powerful ally she needs for her ambitions. The three other members of the 7th Squadron--Himari, Shishu, and Nei--have also come to accept Yuuki's presence among them, adjusting to having a man join their previously all-female unit.

No, there is no post-credits scene in Chained Soldier Season 1, Episode 1 "Birth, Yuuki, Awakening." References to end credits scenes in discussions pertain to later episodes or Season 2, such as a teaser implying danger, but none are documented for this specific episode.

No, Chained Soldier season 1 episode 1 is not family friendly and is rated for mature audiences only, typically 18+ due to explicit content unsuitable for children or sensitive viewers.

Potentially objectionable or upsetting aspects include: - Graphic violence with monstrous creatures, attacks, injuries, and bloodshed during combat scenes. - Explicit sexual content and highly sexualized depictions of characters, including over-the-top sexual situations and BDSM themes integrated into the narrative. - Nudity and frequent sexual themes presented in a sexualized context with power dynamics. - Intense, scary supernatural elements like demonic monsters, otherworldly threats, and a dark, perilous atmosphere. - Introduction of an underage character (11 years old) in a series with pervasive sexualization, raising concerns for inappropriate context.