Squerrik's shamans may only memorize and use their spells in ratman form. They are not organized into any hierarchy, but lower-level shamans learn from higher-level ones and must show them respect and deference (and make offerings of treasures). Wererat shamans must be self-protective. They actively acquire protective magic and anything that aids their skills of concealment and disguise.
His second edition spheres were Animal, Charm and his Portfolio is thievery and concealment. His alignment is LE just as wererats are.
His shamans tend to have skill in hide and move silently to a degree. They skulk and hoard like rats. His avatar uses a short sword so I would imagine that is the favored weapon of his clerics. He is a lesser power and his domain is in Gehenna. (on the first layer, Khalas)