Warren Keffer was a Starfury pilot on Babylon 5.
Near the beginning of 2259 he was involved in a standoff with the Minbari warcruiser Trigati. 
Later while in hyperspace he saw a strange object, black against the backdrop of hyperspace. He became determined to find out what the spacecraft really was. 
While Babylon 5 became a party to 25,000 GROPOS, Keffer shared his quarters with Large and Yang. These two new friends of Keffer were tragically killed in Operation Sudden Death on Akdor. 
Keffer used much of his off-duty time looking for the mysterious ship.  When this became known to the command staff, Keffer was ordered to stop. 
At the end of the year he discovered that it was a Shadow Battlecrab, which then destroyed his ship. The footage from his ship was released on the ISN soon afterward. 
Despite the ultimate price that Keffer paid for this evidence, the footage was shortly removed from syndication. 
Keffer apparently had a wife or a girlfriend back home.