There aren't avatar items in the cash shop. .__.;
And you don't pay for Dark Knight armor.
Dark Knight is a transformation skill for humans that have completed G3.
Right now, all transformation skills are free in every server.
It used to be that you had to have a Nao service to transform, but
with the Na version making it free, all the servers allow players to transform
without having to pay/buy a Nao service.
Character Rebirth cards are really just Character Cards.
You can use Character Cards to rebirth your character or
you can wait until your character is 20 years old to do a free rebirth.
I don't know about the TW version, but KR Version and NA Version
has the 20 year old free rebirthing system





