Tsukasa Kotobuki is a Japanese manga artist, character designer, and animator born on April 28, 1970, in the Tokyo metropolitan area. He began his creative career during his junior high school years by creating doujinshi, or self-published works, under the initial pseudonym Sushi, which is written with the kanji for "sushi." He later changed the writing of his name entirely to the hiragana script, becoming Kotobuki Tsukasa, to avoid the original kanji sequence being misread. Around the age of twenty, he gained professional experience as an assistant to manga artist Kenichi Sonoda, creator of Gunsmith Cats. Following this apprenticeship, his friend, animator Masami Obari, brought him onto the staff of Fatal Fury: The Motion Picture, where Kotobuki worked on costume design and character design. This project helped launch his career in animation.

Kotobuki is credited as the original creator of the anime and manga series Cyber Team in Akihabara. The anime television series, which he co-created with Satoru Akahori, aired for 26 episodes from April to September 1998. He also wrote and illustrated the series' manga adaptation, Cyber Team in Akihabara: PataPi!, which was published in Kodansha's shoujo magazine Nakayoshi in 1998. The franchise expanded to include a video game for the Dreamcast, Cyber Team in Akihabara: PataPies!, for which Kotobuki is also credited. A film sequel, Cyber Team in Akihabara: Summer Vacation of 2011, was released in 1999. His role in the franchise encompasses both the original concept and the visual realization of its characters.

Beyond this franchise, Kotobuki has a substantial portfolio as a character designer for numerous anime series and video games. His notable anime character design credits include Saber Marionette J, VS Knight Lamune & 40 Fire, and Godannar. In the video game industry, he is known for his work as the official illustrator for the Battle Arena Toshinden series. He has also contributed to the Mobile Suit Gundam franchise extensively, working on manga adaptations such as Mobile Suit Zeta Gundam: Day After Tomorrow - Report of Kai Shiden and serving as a character designer and lead animation director for Mobile Suit Gundam: The Origin.

Kotobuki has cited several series and creators as influences on his art style, including Mobile Suit Gundam, Megazone 23, and fellow industry figures such as Masamune Shirow, Masakazu Katsura, and Masami Obari. His artistic identity in the 1990s was characterized by the use of vivid colors, stark contrasting shades, and exaggerated anatomical features, including puffy cheeks that became a trend for depicting cute characters at the time. In later years, his style evolved to feature more subdued and flowing coloring with an emphasis on darker, thicker line work. He has been a guest at major anime conventions in North America, including Otakon in 2003 and A-Kon in 2001, indicating his recognition and significance within the international fan community.