This bug was mentioned in the patch notes for 0.6 this is what Zed said:
If you enter the game and you don’t see any characters, this is because some character that you have on your save file has the same name as one of the default characters. In this current version that is not supported, I haven’t found a way to circumvent this, so for now, the only solution is to not have characters with the same name as the default characters.
If you happen to have a character with the same name as a default character what you have to do is change the name of the character.txt and the jpg image, and also open the character.txt and where it says "CharacterName":"old_character_name" replace the name old_character_name, for the new character name. (the “ are important!). In general I tell people to not edit the characters as it is easy to break something and have the character no longer, but only changing the name shouldn’t be a problem, as long as it matches the file name.
Again, sorry for this issue, I’m trying to find a solution for it.
And that’s all for today, have a great day friends!
And happy holidays!
Cheers!
hope it helps