There was actually quite a diverse selection of horror manga this year, and not all of it is gruesome. Sometimes it was moody and gothic, much like today's selection.
THE BLACK MUSEUM: THE GHOST AND THE LADY (Kuro Hakubutsukan: Ghost and Lady), by Kazuhiro Fujita. First published in 2015 and first published in North America in 2016.
PLOT:
One night, a theater-loving ghost known as The Man In Grey tells his story to the curator of Scotland Yard's Black Museum. In life, he was a duelist plagued by despair. In death, he found himself bound to a young woman called Florence Nightingale. He will defend her from vengeful spirits born from mankind's worst emotions, but if she should ever fall into the deepest possible despair he will kill her. Their bond allows her to survive family opposition, the horrors of Victorian hospitals, and even the perils of the Crimean War, but her greatest threat yet may be another spectre from The Man In Grey's own past.