Every Premium Account receives a promotional bonus that consists in two more character slots.
While normally each account conts 5 slots, a Premium user will be granted to use 2 more slots to a total of 7 usable slots.
These bonus slots will be "frozen" in case of expiring Premium subscription and the player will not be able to use the charaters filling 6th and 7th slots.
Even if you do not renew a Premium subscription you will be able to use 6th and 7th slot character by deleting characters in preceding slots (from 1st to 5th).
Erasing characters causes a positional switch and unfrozes the 6th Character (1 deletion) o 6+7th Caracter (2 delection).
Premium renew, after a pause of any length, will restore promotional slots bonus.