See http://www.games-workshop.com/en-US/Valhallan-Squad for more information.
This is a modification of the German Flamethrower unit found in the World War II folder in the Extras folder in . Instead of fire, the trooper's weapon fires a heavy blast of energy, perhaps a Plasma Gun or Meltagun or something similar. This took longer than usual, and I'm quite happy with the results.
Hmm, with that trenchcoat I would see him as more of a Death Korps or Steel Legion soldier. But then again he doesn't have the protective mask those two armies wear and the Valhallans wear long coats as well, so I guess this can really be a multi-purpose Guardsman.