You may be looking for the patron saint of the same name
Brother Columbanus is the main antagonist of Edith Pargeter's novel A Morbid Taste for Bones - the first in her Cadfael Chronicles series.
Character[]
An ambitious young monk (age 25) within Shrewsbury Abbey (under the service of Brother Cadfael), Columbanus is given to extreme displays of emotion (possibly manic behaviours or even seizures) due to his devout faith.
Near the close of the novel, it is revealed that Columbanus is a murderer. The motives for his murderous behaviours is most likely his ambitions towards power, but could be due to his extreme faith for St. Winifred.
History[]
The younger son of a Norman family, Columbanus was a monk for only a year before the events of A Morbid Taste for Bones. The events of the novel begin with Columbanus suffering from a seizure and setting the monks of Shrewsbury Abbey on the scent of St. Winifred. He joined the voyage to Gwytherin to unearth the bones of Winifred.
While in Gwytherin, Columbanus and his fellow monks were held up by a landowner named Rhisiart. To rid himself (and his fellow monks) of this obstacle, he snuck out of his vigil by drugging his fellow monk (Brother Jerome)'s drink with poppy juice, sneaking out in the middle of the night, and stabbing Rhisiart in the back. Fortunately for Columbanus, a young native of Gwytherin named Peregrin tried to frame another native of Gwytherin named Engelard for this murder.
While Columbanus managed to avoid suspicion throughout most of the monks' voyage to Gwytherin, one monk - his direct superior, Brother Cadfael, figured out what had happened with the help of Rhisiart's daughter, Sioned. To ensnare Columbanus, Sioned pretended to be St. Winifred and gained a confession from the lips of Columbanus. While this worked, Columbanus figured out that the figure of "St. Winifred" was not the real St. Winifred and tried to flee. While fleeing, he was caught by Engelard and accidentally killed by strangulation.
To cover up this death, Brother Cadfael had Columbanus' body exchanged with the bones of St. Winifred.