Zetman is a manga series by the legendary Masakazu Katsura, known for creations such as Dream Fighter Wingman Shadow Lady and DNA. Masakazu also contributed the character designs for Iria - Zeiram the Animation. The show follows Jin and his childhood friend, Kouga, as they both fight evil monsters called the Evol, created by Kouga's grandfather.
The Evol were part of biological experiments and, to keep funding the project, the creatures were made to take part in gladiatorial combat so that rich people could bet on the fights.
Some of the Evol escaped and, using their ability to transform into humans, were able to "disappear". Most were happy to lead normal lives, but some think they should rule humans and start killing people for fun. Jin, who has the power to transform himself into Zetman, giving him greater strength and speed, joins Kouga to fight to protect the city's people from the Evol - but each for very different reasons.
This complex anime incorporates aspects of psychological thrillers and is much more than just another "superguy beats monster of the week" show.
Keep an eye out for it on the airwaves in Hong Kong sometime soon.