Monks cannot use spears. They can use staffs, Rods, Maces, Hammers, Fists and cestus. The Cestus is the only weapon that i know of that does piercing damage for the monk. Of course there could always be an exception.
I did a quest that gave me a claw and I was getting SLASHING skills raising with it. So we could get Piercing, Slashing and Smashing in. I prefer to Dual Fighting Batons though. -Sirlai 15th Brawler - Najena Sanctuary
