Tyranny in Purple is a twenty-one episode/chapter adventure/campaign that takes the PCs from 1st level through 20th level
with the 21st episode/chapter for very strong 20th level parties.
Tyranny in Purple requires none of the hardback books. It uses the Basic Rules, and SRD from wizards.com and free/"Pay What You Want" resources found on drivethrurpg and the DM's guild. There are also elements from Dimgaard supplements that are reproduced so that the DM doesn't need to procure those.