Specialties are what makes it capable for users to interact and use. When choosing a primary Specialty you gain the ability to use any of its forms at a the rank your at. Upon that if fighting someone in that area and you have a primary and they only have a secondary or none. You are given a 10% bonus to all stats against them, a 50% bonus if they have no specialty in that area. Marital Arts however is what is suggested as the primary as it dips into almost every area of combat. From flying to shooting beams. Martial Arts draws a large amount of skills and capability. However it is limited in certain situations such as making things appear and any oddities that would be with Magic or Swordsmanship.
Weapons, however can only be basic and the most basic level at Professional rank at creation, the number of items they want can be within reason. However after character creations a PC can get a weapon of any level as long as they meet the requirements. Another thing is if the user is a primary in swordsmanship or weapon master of kind, may create two weapons one rank below their rank. A a secondary would be one weapon, 1 rank below their rank. Any other items they would add would fall under the rules at the top of this paragraph.
To note world leaders are excused from this rule and may make a weapon at Master Level regardless of their specialties. However if Primary they may craft something at Elite Master level. Secondary allows them to create one Master level and a Elite Lord Level weapons or armor.