Haizen

Haizen (灰泉) is one of five Ayakashi selected to infiltrate Karasumori as part of Kaguro's assassin squad, along with Sanan, Sekia, and Haroku.

Appearance
In human form, Haizen is a bald man with a tattoo on the left side of his head. The head of his demon form somewhat resembles a silkworm, with the rest of his body being black, tall, and rounded.

Personality
He seems to be the least intelligent of the four. He seems to have a hard time remembering speeches, and seems to be uncomfortable in speaking as well. Once he reveals his true form, he doesn't speak at all, even when he was about to be destroyed.

Negotiations with the Kekkaishi
Sekia is one of four Ayakashi that accompanies Kaguro as he infiltrates Karasumori Academy in human form and challenges Yoshimori, Tokine, and Gen. They first visit Yoshimori's classroom, but when they find him absent, Kaguro suggests going to the broadcast room, since they really only need to introduce themselves. Kaguro forces a student to show him how to use the broadcast equipment, and announces to the entire school that a group from Kokuboro has come, instantly alerting Tokine, Yoshimori, and Gen, and causing them to rush to the scene. Gen tries to attack the squad on sight, but Yoshimori stops him, not wanting normal people to see him transform.

That night, Tokine, Yoshimori, and Gen confront Kaguro's squad at Karasumori Academy, only to find them setting up tables and chairs (stolen from the school) for a supposed negotiation. Kaguro gives Haizen and Haroku chances to explain their objective, but both fail. Sanan is the only one intelligent and confident enough to state that Karasumori should be surrendered to them peacefully, so as to avoid unnecessary casualties. Kaguro puts Sanan in charge of the negotiations at that point. Sanan claims they have no desire to harm humans, and even want to become them. Gen suddenly attacks Kaguro, is taken down effortlessly in the space of a second. Kaguro quickly destroys Madarao and Hakubi, and leaves his squad to deal with the Kekkaishi, saying he will kill them if they fail. Sanan theorizes that Kaguro was sent along as their leader to judge their abilities. He grabs Gen, and runs away with the rest of the squad, causing Yoshimori to follow, and Tokine to follow him. The Kekkaishi are lured into a special field that Sanan calls a magic-sealing Kekkai, which prevents them from using Kekkai abilities. Sanan directs the rest of the squad to attack the powerless Kekkaishi, intending to force them to surrender Karasumori.

Tokine attempts to distract the squad while Yoshimori escapes, but Yoshimori is unwilling to watch her get hurt. Instead, he launches her high into the air, where the sealing Kekkai has no effect, and she captures all four Ayakashi with Kekkai, which allows Yoshimori to escape the trap, but Tokine lacks the strength to destroy all four Kekkai at once. Haizen reveals his ability to spit acid from his mouth, which melts Tokine's four Kekkai, and Sanan orders the entire squad to discard their human skin and reveal their true forms. Haizen produces a smokescreen which clouds the field, and then sprays acid into the air, causing it to rain down everywhere. Tokine and Yoshimori take cover beneath one of the large stones that made up the anti-Kekkai trap to come up with a plan. Tokine reveals that she sent a shinigami bird to her grandmother, and is sure she will able to sense the Ayakashi presence now that they are in their true forms. Sanan decides to corner the Kekkaishi by lifting Haizen above the field. Suddenly, Tokine and Yoshimori emerge from the smoke in an Elevator Kekkai, shielded by a Triple Layer Kekkai. Tokine uses her Kekkai Spear on Haizen, and realizing that Haizen is about to be destroyed, Sanan abandons him just before Yoshimori destroys Haizen. Kaguro is disappointed because Haizen was the key to the entire strategy.

Power & Abilities
Haizen produces various substances from his mouth for use in battle.
 * Acid Spray: Haizen sprays a green substance from his mouth that has strong acidic properties, melting down almost anything it touches, including kekkai, which made him the cornerstone of the advance guard's strategy. He can use this in a continuous stream, creating an acid rain effect.
 * Smoke Spray: Haizen can also produce white smoke that blinds his opponents and gives his allies cover.

Trivia

 * In the name Haizen (灰泉), 'Hai' (灰) means gray and 'Zen' (泉) means spring (as in the hot spring).