Invisible. Cloaked riders are naturally invisible. They typically cover themselves with dark robes which gives them form, but if they shed those robes they cannot be seen unless magical means or truesight are employed.
Fear aura. Cloaked riders have an aura of chilling fear which radiates from them to a distance of 40' in all directions. Those who begin their turn in the aura suffer a 5d6 mental attack or are made Afraid. The aura also automatically inflicts 1d6 cold damage to all creatures within 5' of the cloaked rider.
Wailing sickness. Those who suffer a critical hit from a cloaked rider's weapon contract wailing sickness.
Incorporeal. Like all spirits, cloaked riders are incorporeal. They are immune to physical attacks (except those which do holy or fire damage).
Eternal. Spirits cannot be killed; reducing them to 0 HEALTH simply disperses them for one day. To be destroyed a spirit must be permanently banished.