Taking players further along than the Basic, Expert or Companion Sets, the Master Rules Set gives instructions to take your characters all the way from level 26 to level 36. With this comes a lot of added information about spells, monsters and artifacts as well as new rules for your even more powerful characters.

Divided into two sections, one for players and another for DMs, the set introduces new subclasses as well as arms and armour, including rules for sieges and siege weapons. If in the Companion rule you were expected to own a small kingdom, by the time you come to be a Master you should be able to achieve small empires. 

Taking into account the relatively small number of adventures published for this set (and also for the Companion and the Immortals followup set) not many players took their characters as far as these levels, mostly staying around the Basic and Expert levels of the game. Still, this doesn’t mean that there isn’t a lot of fun stuff in here, because there is, it’s just a case of “campaign fatigue”, the same still happens today as most games end around levels 10-12 in fifth edition.