To bring about an end
Winter, 1963 A.D.: Mytilene is besieged. Greek mounted militiamen hilariously try to assist, and are shot.
Across the continent, NDU forces blitz Greek cities. In the space of three months, Norse artillery and bombers hit Salzburg, Syracuse, and Mytilene. Just before the year's end, Mytilene is captured and made part of the DMZ.
Summer, 1964 A.D.: Following the success of Redeemer, the NDU defense ministry enacts two new campaigns. Operation Mountain Thunder looks to capture and hold Salzburg and Herakleia, solidifying the Southern border. Meanwhile, Operation Kraken will target target Greece's coastal footholds along the Viennese coast as far south as Chios, wiping them off the map. The heavily-defended city of Hamburg, Greece (once belonging to now-defeated Germany) is singled out as the probable target for Operation Brightstar. In preparation, the equally-defensible city of Munich will have to be captured for use as an airbase.
Winter, 1964 A.D.: Rome asks for aid on the Eastern front as a coup in leadership has led to renewed hostilities with Russia. Remembering Rome's refusal to join the war against Greece all those years ago, the Norse politely decline.
Meanwhile, massive naval engagements off the continent's eastern coast result in Greece's entire Atlantic fleet becoming fish food. The NDU has effectively seized control of land, sea, and air. Yet, they now butt up against the rocky, stubborn core of Northern Greece, where victory is sure to come at steeper prices.