Nasubi is Karauri's inadvertent colleague. Nasubi can't seems to be able to focus on the given task for a long time and can get easily distracted, which leads him to make mistakes during work.

As pointed out by Karauri, Nasubi is an award-winning artist. However, he chose the job of a minion as it provided stable income for his poor family background.
He is also adept with various paint and craft mediums. His muse and idol is Katsushika Hokusai.

(Source: Hoozuki no Reitetsu Wikia)

Hoozuki is the aide to the great king of Hell, King Enma. Calm and super-sadistic, Hoozuki tries to resolve the various problems in Hell, including a rampaging Momotarou and his companions. However, he also likes spending his free time on his hobbies, such as fawning over cute animals and raising "Goldfish Flowers."
 
(Source: Crunchyroll)

[Wiki (jp)](https://ja.wikipedia.org/wiki/青山桐子)

The second season of Hoozuki no Reitetsu. 

As the right hand man of the Great King Enma, Hozuki’s job is literally a living hell. As the most competent demon in the underworld, it’s up to him to solve problems and invent new forms of hilarious and excruciating torture. 

(Source: HIDIVE)

The second cour of Hoozuki no Reitetsu 2.

In the afterlife, there exists Heaven and Hell. Hell consists of the Eight Greater Hells and the Eight Cold Hells, which are further divided into 272 subdivisions. Spearheading the seemingly endless, multifarious affairs in this gargantuan Hell is but one Fierce God, King Enma's first aide, Hozuki. Between this cool-headed sadist and his colorful band of peers, every day is a riot in Hell! And though this book might make Hell seem like a happening place, please try to behave during life!
 
(Source: Kodansha USA)

Three Hoozuki no Reitetsu OVAs will be released in limited editions of volume 17 to 19, releasing February 23, 2015, May 22, 2015, and August 21, 2015, respectively.

Bundled with the limited editions of volumes 29-31 of the Hoozuki no Reitetsu manga.