Umineko When They Cry, Volume 1: Legend of the Golden Witch

"Each year, the Ushiromiya family gathers at the secluded mansion of its patriarch, the elderly Kinzo. It has been six years since Battler joined his cousins at the annual event, but their happy reunion is overshadowed by worsening weather and an eerie premonition from his youngest cousin-- not to mention their parents' feud over the inheritance. Battler doesn't hold much stock in dark omens, nor does he believe the tales of the witch rumored to have given his grandfather a fortune in gold-- and who walks the halls of the mansion to this day-- But when the eighteen family members and servants are trapped on the island by the raging typhoon, the grisly events that follow leave Battler shaken to his core. Is one of his relatives desperate enough to kill for the family fortune? Or is this the work of the Golden Witch?" -- from publisher's web site.