Chien is a tall, large man distinguished by his massive, rounded belly. His head is bald, adorned only by a single leaf, its stem seemingly sprouting from Sian's very nape and then spiralling up to the top of his head, and he has dark, thick bags under his eyes, which tend to retain a sleepy expression; his nose is rounded, and his jaw squared and thick. His well-built, somewhat slender arms are notably long, almost reaching down to the ground; in comparison, his already small, stocky lower body appears even smaller. Chien bears tattoos on both shoulders, each representing a stylized leaf shape, reminiscent of a heart placed upside-down.
Chien wears a dark tank top on his round torso, complete with light sections in correspondence to the edges and belly area, and bearing motifs identical to his tattoos on the chest and upper back; this very same emblem appears on the leather armbands cirling each of his forearms. A scarf is wrapped around his neck, its ends secured on the front by a thick clasp: this appears to be a small, studded drum, complete with two sticks secured to it via ropes. Chien's attire is completed by plain, somewhat loose light pants, getting tighter close to their prominent hems, and dark shoes. He carries around his Dark Bring, Dux Dormir, in the form of a pendant hanging from his neck.
Befitting his Dark Bring and his fighting style, Chien loves sleeping, and can become annoyed or even angry if someone wakes him up for matters he considers trivial. He is cruel and ruthless, and shows no qualm in viciously brutalizing his defenseless opponents while they are rendered asleep by Dux Dormir. In contrast to his brutish appearance, he is somewhat analytical, seeing through Branch's attempt to pass the prisoner Nagisa off as Elie, and managing to work out Koala's plan to discover the Liberation Army's headquarters without the latter needing to tell him.
Blue Guardians arc
Chien is in charge of the Blue Guardians airship which Branch boards alongside a prisoner Nagisa, pretending the latter is in fact Blue Guardians' target, Elie. Having seen through Branch's deception, he locks him and Nagisa in a cell, ordering the former to make the bound and gagged girl reveal the location of the Liberation Army's base. Chien then relocates to the airship's main deck, where Koala informs him the Rave Warriors are coming to save Nagisa. Seeing the attack as a lucky opportunity to capture Elie, Chien orders all doors to be opened, in order for the opponents to infiltrate the airship and end up in his grasp. The plan works out, with some of the intruders, led by Haru Glory and Let Dahaka, making their way to his location, while the others try to reach Nagisa's cell. With Koala having left to take care of the second group, Chien attacks Haru and Let with Dux Dormir, causing them to fall asleep.
Having rendered the dangerous members of the opposing group defenseless, Chien begins brutalizing the sleeping Haru, much to the shock of the Rave Master's comrades. However, just as he contemplates finishing Haru off rapidly, Hamrio Musica appears, visibly enraged by Nagisa's grievous torture at Branch's hands. Largely unfazed, Chien employs Dux Dormir against the Silver Claimer, only to find out that his rage is too great for him to fall asleep. Musica then proceeds to attack the dismayed Chien, knocking him out with one commanding punch. Having regained consciousness shortly afterwards, following the Rave Warriors' departure, he is approached by Koala, who informs him of a plan to find out the location of the Liberation Army's headquarters. His partner's plan soon proves to be effective, much to Chien's delight. However, Viverin's subordinates show fear at the prospect of facing the Rave Warriors, irritating him; Koala seconds them, telling Chien they should regroup with the rest of the Six Guards for the incoming battle.
The now complete Six Guards march on the Liberation Army's base, where they come across the Rave Master and some of his comrades. Having momentarily repelled them, Chien is ordered by Lukan to stand watch at the gate, preventing anyone from escaping. He is soon approached by two of Yuma Ansect's subordinates, believing their leader to be still guarding the gates, and attacked, easily repelling both assailants with a swing of his club. He prepares to make them fall asleep with Dux Dormir, but is shocked to see the effects magically dispelled by Ruby, who appears to fight him.
Chien and Ruby have a brief talk, with the latter accidentally telling the former how he intends to reflect the effects of his Dark Bring back at him. Resorting to only use physical attacks to nullify Ruby's strategy altogether (much to the penguin's shock), Chien tries to assault the small opponent, but is intercepted by Let Dahaka, who takes up the fight while Ruby and Yuma's men move away. Viverin rushes at his new foe and starts fighting him, but his unarmed blows prove to be no match for Let, and the Blue Guardians member resolves to employ Dux Dormir against his opponent; as he's doing so Ruby, who was actually hiding nearby, reveals himself and succesfully reflects the technique back at Chien, causing him to fall asleep.
This proves to be far from beneficial, however: having entered a sleep-walking state, and thus gained access to his Sleep Walking Fist, Chien sends Ruby flying away before turning his attention to Let. Employing his signature fighting style, the sleeping Chien gains the upper hand on the Dragon Race, barraging him with blows and using his Super Teeth Grinder technique against him. Ruby appears again, trying to sneak-attack Viverin, but he easily knocks the penguin unconscious. Having noticed how the Blue Guardians member relies on sensing his foes' presence while asleep, Let focuses to erase his own, depriving Chien of a target, and thus forcing him to wake up. A shocked Chien is then finished off by Let's Secret Special Heavenly Tiger Attack, which knocks him into one of the headquarters' outer walls. Following Blue Guardians' retreat from the place, Chien is brought back to one of the airships by his comrades.
Dark Bring & Abilities
Chien is a member of the Six Guards, Blue Guardians' strongest team, as well as a group whose power is said to rival (if not surpass) that of Demon Card's Oración Seis; an obvious testament to his strength. In addition, he is in charge of one of Blue Guardians' airships, and thus has authority over its crew, with his subordinates referring to him as "Master Chien". While employing his signature Sleep Walking Fist, Chien was able to overwhelm Let Dahaka, a martial artist of great skill and one of the most powerful members of the Dragon Race.
Enhanced Strength: Chien's mass and bulk come with great brutish strength. A single one of his large hands can carelessly squeeze a human head, allegedly being capable of shattering it, or lift a man in the air; he can also swing his club around with enough strength to send two fully grown men flying away. His lower body, while considerably small in comparison to his arms, can performs vertical leaps of several meters.
Enhanced Durability: While initially knocked out by a single, enraged punch from Musica, Chien has proven to be highly durable during his confrontation with Let, enduring a barrage of unarmed attacks from the Dragon Race without losing consciousness or being seriously hindered. While in his sleep-walking state, he shrugged off being struck head on by Let's fire breath, remaining virtually unscathed.
Master Hand to Hand Combatant: Chien is an accomplished unarmed combatant who can perform a variety of attacks, even rather unconventional ones such as body slams or flying double kicks. Under normal circumstances, however, he is nowhere near Let Dahaka's level, as shown during their initial confrontation. His true skills are only unveiled when he sleeps: it's in this state that he has access to his signature Sleep Walking Fist, a martial art described by Let as looking like "random movements", but which might as well represent "the true power of a living creature". This fighting style is highly unpredictable and acrobatic, further increasing Chien's array of attacks (some instances being spinning kicks and headbutts), as well as making his blows heavier, faster and sharper in execution. He can sometimes move around on all four limbs while employing it. Chien's mastery over Sleep Walking Fist is great enough for him to overpower Let; indeed, it was only by waking him up, and thus preventing him from using the martial art, that the Dragon Race managed to defeat the Blue Guardians member.
- Super Teeth Grinder: A rather unconventional Sleep Walking Fist technique which, as the name suggests, has Chien grind his teeth, producing a loud noise which can annoy his opponents (as well as anyone else in the surrounding area) and make them lose their focus, making it easier for him to land his blows.
Presence Sensing: While asleep and employing his Sleep Walking Fist, Chien tracks his opponents by sensing their presence, allowing him to know precisely where they are despite having his eyes closed. This ability, however, can only perceive conscious living beings: if one of his targets were to be knocked out, he would no longer be able to know their location. It was by voluntarily erasing his presence, effectively disappearing from Viverin's "sight", that Let was able to force him awake.
Chien's Dark Bring, Dux Dormir, harnesses the power of sleep, allowing him to generate out of nowhere large numbers of flying leaves, which hone in on his targets, forming spiralling misty curtains around their heads and causing them to fall asleep. Those affected by it will sleep for seven hours, not waking up even if their body were to suffer severe damage in the meantime, akin to a form of anesthesia. This Dark Bring, as noted by Chien himself, lets him disable foes in an instant, no matter how strong they are; he is then free to brutalize the sleeping victims as he pleases, or to rapidly put and end to their lives. Due to Viverin's mastery of Sleep Walking Fist, having his technique somehow reflected back at him (namely through magical means) would simply make him much more of a threat, discouraging such strategy.
It appears a sufficiently strong and intense emotion on the victim's part can completely nullify the effects of the Dark Bring; in Musica's case, as he put it, he was simply too enraged to fall asleep.  In addition, when Chien was subjected to Dux Dormir, his inability to sense Let's presence woke him up; this despite having been asleep for much less than seven hours.
The Dark Bring consists of a plain, dark round gem, secured to Chien's neck by a thin rope. "Dux" is Latin for "Leader", while "Dormir" is Spanish for "To sleep".
Club: During the Six Guards' assault on the Liberation Army's base, Chien was shown wielding a massive wooden club fitting his size. Combined with his great strength, this rudimentary weapon allows him to pack powerful blows, sending his foes flying away.
Battles & Events
- Hamrio Musica vs. Chien Viverin
- Siege of the Liberation Army's base
- Let Dahaka & Ruby vs. Chien Viverin
- The Six Guards' names are French, each coming from a specific animal, which is referenced by their appearance; "Chien Viverin" translates to "Raccoon Dog". His theme, however, is focused around the Tanuki, a racoon dog subspecies closely related to Japanese folklore. The dark spots under Chien's eyes, his large belly and his use of leaves are all references to such animal, both real and fictional.