There's a fairly serious void in the Swords & Wizardry rpg market for 'Eldritch Horror' or at least it was the thought that ran through what's left of my head. Then I remembered 'Eldritch Tales: Lovecraftian White Box Role-Playing' From Raven God Games. If you want to set a 1920's style Halloween one shot. This is the OSR rules set to use.
'Eldritch Tales: Lovecraftian White Box Role-Playing'is right in line White Box Gothic from Gallant Knight Games. Why because it adds the Gothic horror in spades with an OSR Swords & Wizardry twist or two.The late 1900's through the 1930's were really the last golden ages of exploration on Earth. The last places where the Earth's darkest places were finally revealed. And these are the last edges of the map where the Lovecraftian cults might exist. For White Box Swords & Wizardry this is a perfect time to squeeze in a mini game with OSR overtones. Indianna Jones & Call of Cthulhu style PC's whose exploits cover the gamut of occult & supernatural happenings.
"Clerical Liche Armor Class: 1  Hit Dice: 12 - 18 Attacks: By weapon (1d6) Special: See Below Move: 12 HDE/XP: 15/2,900, 16/3,200, 17/3,500, 18/3,800, 19/4,100, 20/4,400, 21/4,700 While the vast majority of liches have mastered the arcane arts of the Magic-User in rare cases, some of them devote themselves to the service of a malign god or goddess with such zeal that they rises as powerful and terrible 42 Eric Fabiaschi (Order #34172416) masters of corrupted divine magic. These are known as Clerical Liches. They are able to cast spells as a 10th level Cleric. In addition, they have also mastered the spells of a Magic-User, though to a lesser degree than traditional liches. A clerical liche can memorize and cast spells as a MagicUser with a level equal to half their normal hit dice, rounded down. This means that a liche with 14 or 15 hit dice would memorize and cast spells as a 7th level Magic-User and as a 10th level Cleric. Clerical liches cannot paralyze with either their touch or aura, but can Turn Undead as a Chaotic Cleric of 9th level, as described in Swords & Wizardry: WhiteBox."
With a clerical liche as the head of cell of a Lovecraftian cult then the PC's are going to have their hands full! What many people don't realize is the global reach of the Cult of Cthulhu.