So I've been trying to see if it's possible to create talismans that can't normally be obtained in the game. As I understand it the game has a chart of possible talismans that can be created and increasing the gem/skill slots past it's limit will turn the charm into a blank charm when equipped...
it doesn't seem possible to create illegal talismans in game anyways. giving yourself a talisman with more slots/skills than is possible will just create a blank talisman for anyone wondering what happens.