How to get "New" character in configuration.exe on desktop

[zal543hyq]

Hello all.
I have a question on "how to change character in configuration" for Ys I and II Chronicles +.

It's Ys I & II Chronicles + for Windows released by GOG.
 When launching config.exe, Feena comes up for Ys I and Lilia for Ys II respectively, and right-clicking them shows "change character" 

After I beated Ys I at HARD level, I tried to change it to another character but in vain.
I would like to know how this "change character" works and how to get another character for it, maybe "Reah"?
Anyone has a clue ?

[Kadae]

At this point I've beaten the game on Nightmare, as well as having completed Time Attack, so I'm not sure if either of those have triggered anything, but I'm able to switch between both Feena and Reah. That said, I've only tried this on the Steam version.