This chapter quite heavily implies that the game has a limited number of NPCs, complete with names, backstories, and physical traits, that players pick from, instead of making their own custom characters. That's a pretty weird way to do a MMORPG.
In the previous chapter the catgirl that was talking with the Rank 2 girl was using the same character as her (cornelia), so that's just how the game works, everyone that chooses the same character has the same starting point and moves along the same story line, what might change is the overall character build.
Ex:
Cornelia might be a more magic oriented character, meaning that any players that choose her might be locked to magic related classes (magic knight, mage, wizard, etc) while the character that our MC uses could be a more strength related character (since his magic is sealed).
Regardless, this could work in an MMORPG, while it's not a common way to do it, this is just a way to choose your alignment, class, appearance and story line. Let's not forget that cosmetics and skins would still exist so you could change the original character quite bit.