Hoozuki is the talented, sadistic deputy of the King of Hell, Enma. He tries to solve various problems in Hell. In his spare time, he takes care of the animals and raises Goldfish grass.
Hoozuki is a tall but slight oni (Japanese ogre) with black hair that parts in the middle and has a horn on his forehead. His ears are rather large and pointed, as are his fangs. Hoozuki's eyes are grey and slanted, with red markings at their sides. These red markings seem permanent as he retains them after washing and during his sleep. He wears a black yukata with red lining and obi with a Chinese lantern ( this represents both his name and symbol)embroidered on the back. He is rarely seen without his toothed metal club which is extraordinarily heavy, but Hoozuki's superhuman strength allows him to wield it easily. It is also noted by many women such as the Stone Princess and female minions think that he is rather good looking. Noted by Momotaro and King Enma to be similar in appearance to Hakutaku. He actually takes great care in his personal appearance.
He is very stoic and serious, rarely losing his cool under any circumstance (though he frequently blows his top whenever Hakutaku or Enma Daio are involved). It is also implied that he is very manipulative, shown in episode 13 where he admits to enjoying working for Enma as his right-hand man, only because this allows him to manipulate and control the Underworld from the shadows. He gets called a sadist often by various people, yet he himself denies it. '
Hoozuki seems to enjoy resorting to violent means to resolving problems, seen when he confronts Momotaro and tells him "This is Hell so let's settle this with violence". Hoozuki sees violence as the fastest way to deal with whatever difficulties he faces and takes sadistic delight in doing so. He is also proficient in inflicting mental anguish verbally, traumatizing Beelzebub so much after their first meeting that the prime minister of European hell vomits blood the next time he encounters Hoozuki. Hoozuki's sharp intellect serves him beyond affairs of the state, enabling him to win any argument and cow potential enemies such as Satan and Momotaro's three animal companions. Those who fall prey to Hoozuki's sharp tongue typically sink into depression, vomit blood or develop a serious phobia of Hoozuki the next time they encounter him.
Hoozuki is portrayed as somewhat unforgiving in nature as well, grinding several of his goldfish plants into juice and feeding them to Enma as punishment for them trying to escape from his garden patch.
Hoozuki is highly skilled in a variety of arts inluding the brewing of herbal concoctions, rearing goldfish plants as well as combat. His management and organization skills are also impeccable, making him the most important man in Hell besides Enma. Hoozuki proves himself to be adept at killing two birds with one stone, using the mountain of left-over offerings of the dead to feed the ten kings of hell, or sending Momotaro to work in Heaven's peach orchard. The minions of Hell typically flock to him whenever they face problems and he proves more than capable of dealing with the variety of dilemmas presented to him with a combination of cunning and brute strength.
Despite his cool and sadistic exterior though, Hoozuki is extremely fond of animals. He expresses disgust, and even outright hatred for humans who abuse animals and treats Momotaro's three animal companions like his friends. In the first episode he is also seen discussing plans with Enma to visit the Outback so he can see Australia's great variety of interesting animals. Hoozuki also admits to visiting a great number of zoos all over the human world during his vacations there, hiding his ears and horns under a hat while telling curious tourists that he is training to be a ninja.
Hoozuki also treats women cordially, seen where he befriends Peach Maki and even helps her to punish the old lady who had been stealing from her ex-work place. When Hoozuki, Enma, Oko, Karauri and Nasubi are trapped in Cold Hell, Oko is also seen wearing Hoozuki's overcoat to help her endure Cold Hell's freezing climate.
Hoozuki seems to prefer women who are resistant to gross objects that typical women would normally shun, complimenting a female show caster on television for being able to study a gigantic grub without flinching. Furthermore, when Stone Princess asks Hoozuki whether he would marry her or her more beautiful sister, Blossom Princess, Hoozuki replies that he will marry the woman who agrees to drink his brain-tissue miso soup. Beauty seems to be of little consequence to Hoozuki compared to his ideal mate's ability to share his eccentric and often gruesome preferences. Despite his sadistic personality, Hoozuki is very popular with women who are attracted by his looks and reserved demeanour.The stripping hag constantly tries to flirt with him to no avail and many female oni in Shugou Hell are seen giggling while staring at him.
Hoozuki is a deep sleeper, but his wrath can be terrible once awakened prematurely. Once on vacation, Enma incessantly invited a sleeping Hoozuki to admire stag-beetles at the window and received a vicious kick that sent him flying as a result of bothering the oni in his sleep. When Shiro, Kakisuke and Rairo venture into Hoozuki's room to ask for a visit to Shangri-La, Shiro nearly dies of fright when Hoozuki suddenly awakens and grabs his tail.
A running gag in the anime series shows Hoozuki getting angry when he is told that he looks similar to Hakutaku.