Ghosts are the worst, scariest monsters one could possibly fight and it wasn't particularly close.

A vampire was a thing entirely of the physical. Dead flesh given false life, yes, but though they would drink your blood and animate your desiccated husk in their service, they generally had no truck with one's immortal soul. The fae, as wild and terrible as they were, have usually been around for thousands of years and so people usually have a fair idea of how to manage their tempers and slake their thirsts. Century Wolves and hippopotami and manticores were mere beasts despite all their magic powers. An Azmych might tie a road into knots and crack the skulls of travellers lead astray, or the Karakoncolos would lash you for your sins, or the the cross-road deviless would... even all of these devils at least interacted with knowable patterns of virtue, vice and the divine.

But a ghost? No law bound a ghost other than the madness of man. A ghost might seek vengeance or eternal cruelty. A ghost might be bound by forgetfulness or grief. A ghost might possess a doll or tempt maidens down a well. A ghost might arise in the fields under the radiant sun or flow through the blood of its children like a toxin. A ghost might teleport, or it might whisper, or it might curse crops, or it might howl with the wind, or it might transform the world into a waking nightmare, or it might crush the unwary under fallen rooftops, or it might imprison its victim forever inside a painting. Only a fool would not be afraid of no ghost.

There are methods, true, but these are less about finding commonality amongst ghosts, who are as varied as the mad, and more about finding aspects of the natural world that interact with them. Dogs, for instance, can see ghosts - and this trait explained a great deal of the behaviour and eccentricities of dogs. A well trained hound was invaluable in exorcism work. There was also the exorcism itself, the recital of which was one of the greatest strengths of the priests of Bloodless Xristos. There were those who possessed close personal connections to the ghosts in question and could divine the methods and messages amidst the madness. There were northern mystics who knew warding runes, and Persian clergy with their sacred fires. 

Robena possessed none of these. Her method for dealing with ghosts has historically been absolute terror, blind fumbling, and outrageous luck. This strategy has met with far more success than its components merited, and tales of its success have been further punched-up by Yomdaeler who bragged that even the immortal dead would know her legend. Alas.

[My right to be known by reputation extends to even the dead. Alas, a two.]