Kenichi Sonoda is a Manga artist from Japan who began his career with a nascent Studio Artmic (which later became AIC), where he was the character and mechanical designer for Bubblegum Crisis, Gall Force, Riding Bean and Gunsmith Cats, also penning the manga for the latter two on his own. The last one is probably the work he is most famous for; GSC has put out thirteen manga volumes over the years and the main character, Rally, is one of the definitive Action Girls of manga. Bubblegum Crisis would be his second-most-famous, especially to American viewers; he only worked on the original and Bubblegum Crash, however, not Tokyo 2040. In the interregnum between the messy split between Artmic and Youmex (which killed Bubblegum Crisis stone dead), in 1991 he agreed to help out a struggling set of rookie animators who called themselves "Studio Gainax"... and agreed to do the character design for a little OVA of no consequence at all called Otaku no Video, resulting in probably his third most famous work.
Sonoda is famous for a few things, the first of those being the popularizing of Mukokuseki. The trend may trace roots all the way back to Tezuka himself, but Sonoda is famous for taking that bull by the horns and running with it. This is due in part to his casts often being incredibly multiracial (like the Knight Sabers, who are all at best only part Japanese, or Rally of GSC, who is Indian-American). Even with Otaku no Video, though, he had a tendency to draw even Japanese people without any defining Japanese traits at all (at a time when many manga and animated works in Japan still tried to make the characters look somewhat Japanese, even where it didn't make a lot of sense). The influence of his works led to a much wider acceptance of portraying a much wider variety of characters in manga & anime, particularly females, for better or worse.
The second thing he's famous for is attention to detail. Sonoda is a self-professed gun, car and general engineering nut (and boy, does it show in his work) and takes pains to model every single mechanical device, be it a gun, a car, a motorcycle, a computer or a hardsuit as realistically as he can. His influence is part of the reason the BGC hardsuits look like they'd work; he took the time to model their internals with exacting detail. As for Gunsmith Cats, well, the "gunsmith" part of the title isn't just for show. It's seriously almost a Gun Porn parade throughout the entire series. (As befitting a Super Robot manga, Cannon God Exaxxion takes this Up to Eleven.) Depictions of firearms in comics in general (not just manga) are often stacked up against the standards he set in his works, particularly GSC (and are usually found wanting). He's a large part of the reason many artists and animators try to make their guns look more than "generic".
Finally, he's a bit infamous for... well, you might look at his famous works and note how much of the cast is female-centric. Sonoda is a bit famous for piling on the sexy a little with his female cast members. Bubblegum Crisis is probably the most infamous for this, with a fair few topless shots while our heroines get into their hardsuits. Truth be told, today it'd all seem pretty mild, but for The Eighties it was all pretty provocative, and he didn't back off that much after going pretty much manga-only. (Being a longtime contributor to one of Japan's most famous Seinen anthologies helps you do this without complaint.)
However, lest the reader get the idea that he was famous for being exploitative, Sonoda was also one of the first artists and manga-writers to portray very strong and independent women as protagonists in an unabashedly positive light. As a reminder, his two most famous protagonists are Priscilla S.Asagiri and Rally fuckin' Vincent; we'll just leave it at that.
Sonoda was very prolific in The Eighties and during the first part of The Nineties, but he's slowed down in recent years, partly due to age (he's 48 years old now) and partly due to the difficulties that occurred when Artmic became AIC, and all the bad blood with Youmex that ended the run of Bubblegum Crisis prematurely. He did pen all of Cannon God Exaxxion later in The Nineties and into The Noughties and the five most recent Gunsmith Cats manga volumes in the middle of The Noughs, but other than that he hasn't been up to much, especially on the anime side of things (aside from a brief dabble with Solty Rei and a bonus manga to be included in the Blu-ray re-release of Riding Bean). He's apparently involved in the Bubblegum Crisis movie in development currently, however, and there's hope he might return to the table for a new, "proper" continuation of the OVA series at last.
As a final note, many of his manga works aren't that hard to find legally in English; Sonoda has had a long, positive relationship with Dark Horse Comics (and even helped them out with their Bubblegum Crisis: Grand Mal original manga) and they've published all of his major manga works, save for the last two volumes of Exaxxion due to a massive shitstorm that erupted over their censorship of a sex scene.
- Gall Force (1986 to 1991)
- Wanna Be's (1986, and no, that's not a typo)
- Bubblegum Crisis (1987 to 1991)
- Bubblegum Crash (1991)
- Riding Bean (1989)
- Otaku no Video (1991)
- Gunsmith Cats (1991 to 1997, manga; 1995 to 1996 OVAs)
- Gunsmith Cats Burst (2004 to 2008)
- Cannon God Exaxxion (1997-2004)
- Solty Rei (2005, credited as "Conceptual Design")