Harvey Severson was a male human in Starfleet in the 23rd century. He was a rail-thin, pale-complexioned man of Swedish ancestry. In 2268 he was a senior Admiral in Starfleet. As a flag officer, Severson oversaw Operation Vanguard and was Admiral Heihachiro Nogura's supervising officer at Starfleet Command, whom Nogura viewed as a desk-bound bureaucrat. As Nogura's superior, Severson called Nogura "Chiro" - something which annoyed the Japanese admiral. (VAN novel: Storming Heaven)
Severson was a hawk with strong beliefs in the Federation's security and supremacy over foreign powers, especially the Klingon Empire. Severson ordered Nogura and the Vault scientists to use the replicated Eremar Tkon array that year to use it to capture the Shedai - in the words of Carol Marcus to "enslave" the Shedai. When Nogura's staff succeeded in capturing all the Shedai, giving the array untold potential for destructive purposes, he passed onto Nogura the thoughts of the New York-based Starfleet Research and Development team's ideas for militaristic tests. Overruling Nogura and Operation Vanguard's head scientist, Ming Xiong's objections, he ordered them to use the array to destroy a test planet in Federation space. The test ultimately led the Tholian Assembly to attack and destroy Vanguard, as the xenophobic aliens realized the Federation had no desire to destroy the Shedai, but to merely use and abuse their power. (VAN novel: Storming Heaven)