Maybe your concept of "Master" is not precisely the same as HMaster. The HMaster is for administrative purposes, such as identifying which RegionServer contains the Region for a given set of rows of a give table.
All of the data in the rows of any of your tables will be inside RegionServer's. Reading/writing data to/from the RegionServers is accomplished without any interaction with the HMaster except to determine which server the rows live on.
Coming back to your "master" vs "slaves" machines topology: you might decide to store the sequence prefixes as separate tables. Then the RegionServers for the prefixes may be managed separately from the sub-prefix trees . In any case there is not a "single master machine" to store the data but instead one or more Regions on one or more RegionServers.