The following account from ‘Haunted Churches’ (1939) by Elliott O’Donnell (27 February 1872 – 8 May 1965) refers to a Devil tradition associated with three churches in close proximity, though he does not name the individual church.
‘The Devil is said to have been seen, during the last century, hovering around the churchyards of Rhosygarth, Llanilar and Lledrod, sometimes in the form of a tall man in black with a white, evil face, and sometimes in the guise of a figure with the trunk and limbs of a man and the head of a wolf, or dog. Very possibly it was not the Devil but what, for want of a more accurate name, modern writers of works about the superphysical term an Elemental. Be that as it may, it must have been very startling, for some of those reported to have seen it were ill for a considerable time afterwards, one or two never recovering.’
In the case of Llanilar, he may be refereeing to the St Hilary’s Church (Eglwys Sant Ilar (Church of Saint Ilar)), which is a Grade II listed building probably dating from the 14th century.