Kengo Ibuki was Rei Hino's cousin, who only appeared in episode 183. He worked with pottery, but suffered from violent fits of rage, to the point of smashing all of his own creations, should one be even the slightest bit off. His Star Seed was taken by Sailor Aluminum Seiren and he subsequently transformed into the Phage Sailor Artist. While transformed, he went on a wild rampage through a lakeside campground, destroying campsites and disrupting a movie being shot by the Three Lights. He was saved by Eternal Sailor Moon and Sailor Mars, and then returned to a slightly more peaceful life.
As Kengo did not appear in the manga, he is believed to be an anime-only relation of Rei's.