The official GemStone IV encyclopedia.
A creature of darkness, the wraith shies away from the light, preferring to ambush and rend its prey in the safety of the deep shadows. Its crimson eyes glare hatefully at the world around it, while its tortured grimace displays sharp, gleaming fangs. Proficient with weaponry, a disarmed wraith is still a formidable foe, as its long, sharp talons indicate.
Hunters should use classic 'stance dance' methods, dropping to offensive for casting/channeling and returning to guarded or defensive to await the next incoming attack before repeating until the wraith is dead. This compensates for the high casting ability and fair AS of the creature.
AS and CS will be different for each type of attack or spell that the wraith casts. Some recommended spells include Spirit Warding I (101), Spirit Warding II (107), Elemental Bias (508), Resist Elements (602), and so on.
Good offensive spells to use include Mana Disruption (702), Disintegrate (705), Minor Fire (906), Energy Maelstrom (710), and Sandstorm (914).
As these are undead, holy water and other bolt/flare attacks also work well.
Prayer of Holding (301) costs 5 mana when cast against a wraith. Considering it lowers their DS significantly and prevents them from casting, however, it is well worth it.