[icra]

Well, if you are using MySQL, YSI_INI or whatever doesn't change nothing. The logic is still the same.

Create a folder/table and call it - for example - accounts.
Inside accounts you have got users credentials (username / password)

Create one more folder/table and call it - again for example - characters.
Inside characters you have got characters linked to accounts (roleplay name / account username)

Create a login algorithm which allows you to log in into your account (trough table accounts, using username & password credentials)
If you succesfully log in, you'll have a list of all you characters, estrapled by a SELECT (SQL) for example.

Then, trough a dialog, you'll be able to choose your character.
For example, you'll see:

Character 1
Character 2
Character 3

If you choose character 2, it spawns you trough your "characters" credentials.
It's not that hard, but i suggest you using MySQL since it's faster for things like this.
INI is really heavy and slow.