Playing a saint is a bit difficult because the character class never uses weapons, never dons armor, and never fights.
Rather than being easier pickings in the ridiculously monster-choked world of Arduin over the rest of the poor adventuring sods, the saint get natural protection -- a naturally increasing Armor Value (AV) as one progresses in level. The saint may also don armor or artifacts that increase AV, provided they are holy artifacts consecrated within the saint's religion.
In addition, the saint gets a plethora of unusual abilities that grow as the saint goes up in level, some of the more significant include:
- an ever-increasing ability to pacify all those in the range of the saint's voice (pacification means that those affected will stop fighting);
- immunity to undead- or demon/devil-inspired terror;
- the ability to read magic automatically, and to speak in an ever-growing catalog of tongues;
- an arsenal of senses and detect abilities: undead, evil, and poison, infravision, direction, and weather
- at higher levels, the ability to walk on water, walls and sheer surfaces, and even phantasmal surfaces
- at higher levels, the ability to exorcise by force of will alone -- first lesser demons, then later greater demons
- at higher levels, increasing to eventual total immunity to undead paralysis, mesmerization, and life force drain
As an aside, I remember having an ability to "hide like a saint" -- rendering my character effectively invisible after declaration so long as I did not attack (which I obviously wouldn't) or speak (which I might) -- but can no longer find it in the rules. Was it a house rule from my old group? I may never know.
Arduin was a funky place to adventure, but a fun one.