Nurarihyon no Mago Chapter #3
Nurarihyon no Mago Episode #2
Anime, Manga and Game
Zen is a poisonous bird yokai who specializes in making medicine. His species has a short lifespan, causing him to become weaker as he ages. He and Rikuo were childhood friends, and he is known to vomit blood when very angry or emotional. Due to Zen's poor health, Rikuo often doesn't inform him of upcoming battles and there's a running gag in the series whereby Zen has angry (blood-vomiting) fits as a result.
Zen has khaki, scruffy hair that turns black at the neck and deep red eyes with small pupils. His skin is pale and he usually wears a purple kimono and a dark blue Haori with red details along the sleeves and collar.
Zen is hot-tempered and excitable till the extent of vomiting blood on occasions, but can be calm when he needs to be. He is Rikuo's sworn brother as they grew up together, resulting him being fraternal towards the latter.
Exposition Arc Edit
At Nurarihyon's behest, Zen visits the Nura House to talk to Rikuo about becoming the 3rd heir. He becomes both disappointed and angry that Rikuo has no intentions of taking up the position and has become so kind-natured. Frustrated, Zen leaves with his subordinate Hebidayu to return to Yakuzen Hall, revealing on the way that his health is growing worse. Shortly after arriving home, Zen is attacked by Hebidayu and the latter's supporters, who believe they can overpower Zen and take over the Yakushi Clan for themselves.
With Yakuzen Hall in flames, Rikuo appears overhead in Oboro-guruma (having followed after Zen to apologize and explain things in full). Though Zen yells at him, believing that a human is incapable of helping in the current situation, Rikuo transforms into his night form and dispatches with Hebidayu. Zen is struck by the difference between Rikuo's two forms, and Rikuo states that he will protect Zen, who is a weak yokai. The two end up performing a 50:50 sakazuki as a symbol of their brotherhood.
Zen tends to Rikuo when the latter collapses under the pressure of being the Nura Clan's temporary leader, and subsequently tells Rikuo to form his own Hyakki Yakō.
In the anime, Zen accompanies Rikuo's forces into battle against the Shikoku Hachijūhakki Yakō and uses his feathers to heal his allies. In the manga, Zen remains at the Nura House along with the other board members and is amused to see Hitotsume Nyūdō and Mitsume Yazura frustrated over Rikuo's victory.
Kyoto Arc Edit
He secretly stows away aboard Takarabune in order to follow Rikuo's forces into Kyoto. When Itaku and Kubinashi break out into a fight, Zen stops them by splashing them both with medicine - essentially overpowering them with his "fear." Rikuo comically smacks him for coming despite his weak body.
After Rikuo is defeated by Tsuchigumo, Zen acts as medical support during Rikuo's rigorous training with Gyūki and the Great Tengu of Mount Kurama. When the latter grows impatient and sends his subordinates to take Nenekirimaru by force, Rikuo tries to get Zen to flee, stating that he will cover the other's escape. Zen, however, refuses to leave and declares that he wants to fight alongside Rikuo, as part of his Hyakki Yakō. Rikuo ultimately accepts Zen's determination, which leads to them performing matoi. Zen joins Rikuo again during the latter's rematch with Tsuchigumo, entering Tsuchigumo's spider web barrier with Tsurara. He is later among the yōkai who march on Nijō Castle.
Shibuya Arc Edit
Zen stays at the main house to heal injured Nura Clan yōkai.
After the ending of the manga's main story, Zen reaffirms his old bonds with Rikuo and Shoei. He also reveals to Shoei that the strain of the recent battles has taken its toll, and he expects to die before long.
As Zen has a weak constitution, he is poor at actual combat (despite having once used a sword to try and fight Hebidayu). Instead, he can utilize his poisonous wings and extensive knowledge of herbs and plants.
- Poison Wings: Zen's feathers are extremely poisonous - so much so that just touching them can cause adverse effects. Other yōkai who are aware of this tend to avoid him when he is visibly infuriated, as he can shoot off his feathers like arrows. Zen's wings are usually kept retracted into his body, visible only as a series of vein-like black lines across his shoulders and back. He doesn't use his feathers for offensive purposes that often, but performing matoi with Rikuo enables the latter's use of a sword enveloped in a poisonous aura.
- Healing: Though the anime shows Zen also utilizing his feathers as healing implements, more often than not his healing techniques are due to his extensive knowledge of plants and herbs. He can make all sorts of salves and medicines and has years of experience behind him. Even as children, Rikuo was amazed at Zen's knowledge of poisonous and beneficial plants.
- He ranked 7th in the first character popularity poll with 406 votes. With 912 votes, more than before, he also ranked the 7th in the second character popularity poll. During the third popularity poll, he ranked 3rd with 1,820 votes.