The number of characters is initially limited to 5 on every DOFUS account. The add character service allows you to add an extra character each time you purchase the service (within a limit of 32 characters per server type).
For example: an account can create 32 normal characters, 32 heroic characters and 32 epic characters if 27 extra slots are added to the 5 initial slots.
This service is valid for life and costs 6,000 Ogrines.
Ogrines allow you to buy various services for your Ankama account and/or your characters. The full list of services available can be found in the DOFUS Shop.