Who created him? Valérian: agent spatio-temporal born in 1967 by the works of Pierre Christin (text) and Jean-Claude Mézières (illustrations) and is published on Pilote, illustrious French bande dessinée magazine. The series achieves at once an outstanding success and succeed in take up a niche - the Sci-fi genre - which till that moment have had only a marginal place in the BD wih a single series - Les Pionniers de l'Espérance - repetitive and not much interesting. Moreover, a feminine character become popular, Laureline who, from a first appearance which presented her as a side-character, assumes a protagonist's role, undermining a place that in the genre was occupied only by Barbarella, but this time without using the typical tricky "weapons" of the feminine gender but only a sagacious shrewdness and wisdom, as well as an intimate sensuality.
The adventures have been later collected and published in albums and, besides the regular series, the short stories, the little sagas spread over many albums, the couple of authors have enlarged the environment which acts as a background for the series with specials and books of maps of the fantastic worlds visited and of the alien beings met.

Who's he? Valerian is the best space-temporal agent of Galaxity, Earth and Earthly Galactic Empire's capital city in 2720. His tasks are to patrol history to prevent that someone could modify it for personal goals and to discover new resources for his Planet. So, he is continuously busy in travel back and forth along time and in explore the unknown space, taking contact with new alien races or with individuals of other Earth's periods.
All this till a disaster, told in the album "The Thunder Of Hypsis", that devastates Valerian's life altering and erasing the future as he had knew and the whole Galaxity! By the time alone with his girl-companion, the adventures of the couple goes on in an aimless roam.

Who are his friends? They are many and not quantifiable. The most important is certainly Laureline. Thanks to her, Valerian survived a trap in the Arelaun Forest, an inchanted wood in 11^th century, during the first story told, "The Bad Dreams". Since then the two never parted and they form a solid couple: more than a friend, she's the companion. There are also his colleagues of the timespace agency and his superiors, like the technocrats. Honestly, almost all of the characters sporadicly met in their adventures are friends, like Sun Rae, a 20^th century's gangster, or professor Schroeder, the Alflololians or the little Caliph. But the complete list would be too long.
A place of honour is up to the most recurring ones like the three Shinguz, the Bluxte's grognon trasmutator and the loyal Mr. Albert.

Who are his enemies? Not much. Actually the so-called "rivals" have almost ever a valid reason for their actions and often the conflicts are only ideological differences that come to fight, or different point of view between the parts. Nothing, anyhow, that the couple could not remedy with the reason and a bit of action. The reason of the absence of real enemies is also in the typology of their adventures: no fights against someone to defeat, but situations to live or to work out.
Valerian's main foe is, without any doubt, Xombul, the technocrat which appear in the first and in the second adventure ("The City Of The Moving Waters"). And besides the group called Quator Mortis, which appeared in "The Hostages Of The Ultralum" and in the sequel "The Orphan From The Stars".
Reading the series issues it seems that the real enemies are not monstruous beings coming from the sidereal abysses, but the closer human beings...