Kengo Yonekura is a Japanese manga artist and illustrator, born on July 23, 1975 in Tokyo, Japan. Yonekura is a female creator who has worked across several genres and demographics, including adult manga, yaoi, and later mainstream American comics. She is known to use multiple pen names, including Natsuo Imamura for general manga and Ricken for her work on American comics. Her doujinshi circle is named KyokenDINERz.

Yonekura is credited as the original creator of Warau Kangofu The Animation, a two-episode original video animation (OVA) released from October 2007 to January 2008. This anime adaptation is based on her manga of the same name, a collection of short stories published in Comic Megastore from 2002 to 2005. The manga and its adaptation fall within adult genres. Beyond this work, Yonekura has authored several other manga titles, including Pink Sniper, Yellow Hearts, and Fire Candy, the latter of which was published under the name Natsuo Imamura. She was also responsible for the character designs of the visual novel Kana...Imouto (also known as Kana... Little Sister).

Yonekura's artistic career began with yaoi doujinshi intended for a female audience before she transitioned into creating professional adult manga aimed at male readers. Her work is noted for its high-quality artwork and what some describe as a feminine touch within a genre predominantly created by male artists. A recurring element in her manga is the depiction of relationships between older women and younger men, a dynamic sometimes referred to as Oneshota. She is also recognized for her specialty in drawing characters with plump lips.

Yonekura's career is notable for an unusual professional trajectory: after establishing herself in the Japanese adult manga industry, she began working for DC Comics, an American mainstream publisher. Using the pen name Ricken, she created cover and interior art for DC, notably on the Transformers franchise, making her a rare example of a Japanese creator crossing over into American comics.