Roger Leloup, born in Verviers, stands out for the highly detailed and technical drawings in his trademark series 'Yoko Tsuno'. In the early stages of his career, he was mainly doing background art assistance for other artists. He helped Jacques Martin on 'Alix' and 'Lefranc', and from 1953 to 1969, he worked at Studio Hergé, where he was responsible for the airplanes in the 'Tintin' episode 'Vol 714', among other things. He then worked at Peyo's studios for a short period, and assisted Francis on his work for J2 Jeunes, Le Soir Illustré and Spirou. During the same period, he created technical drawings for both Tintin (1954-57) and Spirou.
For Spirou, he created a series about a Japanese electronics engineer, 'Yoko Tsuno', which first appeared in 1970. From then on, he practically devoted himself entirely to this comic series. Leloup showed a talented artist of detailed spaceships and science-fictional landscapes.
Throughout the series run, Leloup alternated his stories containing adventures on other planets, with stories set on earth, that were often related to Yoko's Japanese origins. Roger Leloup also wrote some novels about 'Yoko Tsuno', in which he deepened the character's personality and background.