Other fictional characters may not be immediately protectable under trademark law since they are not inherently distinctive and have not yet developed secondarymeaning.
In particular, a designer may first seek and secure a design patent and then secondarymeaning for trade dress protection of the design can be developed during the 14 years of design patent protection.
Card coverage tends to be secondary, meaning that if the renter has any other applicable insurance it must be tapped first to pay for damages, with the card picking up deductibles and extras like towing.