North Window was once a large town, on a par with South Window City. In 449, Neclord laid waste to the town in a single night along with a host of zombies. The people were transformed into zombies and would turn on each other, leaving no survivors.
Viktor was one of the few people not to be present during the massacre but returned in time to see the transformed villagers and was forced to cut them all down. A South Window City force would be dispatched following this in order to mop up any remaining zombies. Following this, Viktor set out on a journey in search of revenge and at the end of a long quest, would (twice) enact his vengeance.
Official knowledge of Neclord's appearance and the reason behind North Window's destruction would be suppressed by agreement of the member states of the City-State of Jowston, giving the mystery of North Window an enduring presence in people's minds. Following the destruction of the town, it was left as ruins for years with only an old castle remaining standing in some form.
The deserted ruins of the town became subject to rumors of disappearances during the Dunan Unification War, which were found to be caused by Neclord. After he was driven off, the remains of the town would form the basis for the headquarters of the New State Army.
Genso Suikoden I & II Official World Guide Book (ISBN 4-471-36033-7), page 56
Genso Suikoden Short Story Collection 1 (ISBN 4-8402-1494-8), pages 261-340
Genso Suikoden Encyclopaedia (ISBN 4-575-16297-3), page 206
Genso Suikoden Kiwami Encyclopedia, page 192