David Gunn is the author of the military science fiction Death's Head series.
Sven collects a symbiont and an intelligent gun in the course of his adventures, as well as a group of other soldiers known as "The Aux" (for auxiliaries.)
Sven is 98.2% human and 1.8% "something else" and is able to tolerate, and quickly recover from, major physical stress and damage.
Sven is an adherent of the Octovians, named after Emperor OctoV, who appears to be a fourteen-year-old boy but is actually something much different.
The brief biography of the author provided by his publisher states that Gunn comes from a service family, that he has undertaken assignments in the Middle East, Central America, and Russia, and that he lives in the United Kingdom.