Gen Shishio's Last Stand

Gen Shishio's Last Stand (志々尾限最後の戦い, Shishio Gen Saigo no Tatakai) is the 37th episode of the Kekkaishi anime adapted by Sunrise.

Summary
After transforming, Gen Shishio is shocked that Yoshimori and Tokine still accept and support him. Yoshimori volunteers to take care of Gagin's giant fireball while Gen handles Gagin directly. Gen points out that Yoshimori's Kekkai couldn't stand up to Gagin's power earlier, but Yoshimori insists that he will succeed this time. As Gen prepares to fight Gagin, he is amazed at how at peace and in control he feels, since he normally goes wild after transforming. Just then, Gen's egg hatches, releasing an Ayakashi Insects. With his doubts gone, Gen simply crushes the insect.

Byaku and Shion observe this, and Shion wonders if this is a bad thing. Byaku isn't concerned, confident Gagin will take care of everything. Tokine is worried about Yoshimori and Gen being too reckless, and promises herself that she won't become a burden. Yoshimori surprises her by admitting that while it might be better for her to hide somewhere safe, he'd rather have her by his side. Tokine encourages him in return, giving him new confidence.

Gagin launches his fireball, and Tokine immediately place Kekkai leading into the sky, allowing Gen to leap between them. Gen strikes a major blow against Gagin. As the fireball approaches the ground, Tokine tells Yoshimori to keep his Kekkai parallel to the ground, so he can deflect the attack with the least amount of effort. Instead, Yoshimori creates his Kekkai at an angle, so that it takes the fireball directly. He says that since Gen is risking his own life, he has to do the same.

Meanwhile, Shigemori defends the Sumimura Home from Shion's spider goons, but is surprised to notice that Tokiko has not appeared to get rid of the ones around the Yukimura Home. Shigemori rushes into the house, and is startled to find Tokiko's Shikigami clone, who tells him that Tokiko has gone to Kurosusuki, leaving her to protect Shizue. After destroying the remaining spider goons, Shigemori leaves Shikigami as guards, erects a Kekkai that surrounds both homes, and heads for Karasumori. On the way, he is joined by Kyoichi Hiba, who has come to offer support. Masamori and Mukade rush to Karasumori.

Gagin regenerates his arms and shoots fireballs to keep Gen away, then surrounds himself in a flame barrier. As Gen notes that while they are equal in power, he is faster. Suddenly, his flame tattoo starts to burn, reminding him how much power he's drawn on. Gen decides he doesn't care, since he's about to be doused in fire, and manages to strike Gagin through the barrier. Yoshimori finally sends the fireball flying back at Gagin, and Gen tears the barrier open just before the fireball strikes Gagin. Gen's body begins to resist him, and as he closes in to finish Gagin off, Kaguro suddenly appears and stabs Gen through the back with two swords, and gives him one last chance to become allies. Gen refuses, and Kaguro rips the swords free. Gen falls toward the ground, Tokine catches him with a Kekkai. Yoshimori chases after Kaguro, but gives up when he realizes that Gagin is still a threat. Yoshimori traps Gagin with a Kekkai, but Gagin's remaining strength makes it unstable. Tokine uses a Kekkai to detonate the fireball Gagin is charging up, allowing Yoshimori to destroy him.

Gen reverts to his human form, and tells Yoshimori and Tokine not to bother with him, since Kokuboro still has other Ayakashi ready for combat. Just as Byaku orders the army to attack with full strength, Princess breaks free of her restraints. Byaku pleads with her to stop, but she has grown impatient and intends to conquer Karasumori herself. She extends her tails down towards the school. Yoshimori assumes that Gen will heal as long as he's in Karasumori, but after Hiba arrives with Shigemori and sees Gen's wounds, he points out that they should be healing, but aren't. Shigemori surrounds the group with a Kekkai just as lightning strikes from Kokuboro's dark clouds.

Yoshimori tries to convince Gen to live, but he is satisfied that he was finally able to help someone instead of hurting them. Karasumori responds, and Yoshimori recognizes the sensation as the same when Madarao defeated Kouya. Yoshimori realizes that Gen has accepted his fate and begs him not to give in. As Gen passes on, the site is bathed in light, which drives back Princess's tails, causing her to fall ill. Byaku immediately orders a retreat. Masamori and Mukade arrive just as Kokuboro leaves, and accepts responsibility for what happened to Gen. However, he refuses to mourn because Kokuboro could still attack at any time.

Differences from Manga

 * In the manga, Princess does not attack Karasumori, and instead eventually falls ill in Karasumori's presence, causing Byaku to call off the invasion. Instead of being destroyed, Gagin is retrieved by Kokuboro as they escape.
 * As Princess's tails emerge from her carriage to attack Karasumori, lightning appears in the dark clouds around Kokuboro's army, and even targets the Kekkaishi, implying that it is under Princess's control. This is not shown to be one of her powers in the manga.